diff --git a/docs/user_guide/layout.rst b/docs/user_guide/layout.rst
index b3bc6d7b8e..9d63b12417 100644
--- a/docs/user_guide/layout.rst
+++ b/docs/user_guide/layout.rst
@@ -354,15 +354,15 @@ By default, it has the following configuration:
 .. code-block:: python
 
     html_sidebars = {
-        "**": ["sidebar-nav-bs", "sidebar-ethical-ads"]
+        "**": ["sidebar-collapse", "sidebar-nav-bs"]
     }
 
+- ``sidebar-collapse.html`` - a button that allows users to expand and collapse the sidebar.
+
 - ``sidebar-nav-bs.html`` - a bootstrap-friendly navigation section.
 
   When there are no pages to show, it will disappear and potentially add extra space for your page's content.
 
-- ``sidebar-ethical-ads.html`` - a placement for ReadTheDocs's Ethical Ads (will only show up on ReadTheDocs).
-
 Primary sidebar end sections
 ----------------------------
 
@@ -382,6 +382,8 @@ By default, it has the following templates:
       # ...
     }
 
+``sidebar-ethical-ads.html`` is a placement for ReadTheDocs's Ethical Ads (will only show up on ReadTheDocs).
+
 Remove the primary sidebar from pages
 -------------------------------------
 
diff --git a/src/pydata_sphinx_theme/assets/scripts/pydata-sphinx-theme.js b/src/pydata_sphinx_theme/assets/scripts/pydata-sphinx-theme.js
index b71b329737..2452d94144 100644
--- a/src/pydata_sphinx_theme/assets/scripts/pydata-sphinx-theme.js
+++ b/src/pydata_sphinx_theme/assets/scripts/pydata-sphinx-theme.js
@@ -1012,6 +1012,129 @@ async function fetchRevealBannersTogether() {
   }, 320);
 }
 
+/*******************************************************************************
+ * Set up expand/collapse button for primary sidebar
+ */
+function setupCollapseSidebarButton() {
+  const button = document.getElementById("pst-collapse-sidebar-button");
+  const sidebar = document.getElementById("pst-primary-sidebar");
+
+  // If this page rendered without the button or sidebar, then there's nothing to do.
+  if (!button || !sidebar) {
+    return;
+  }
+
+  const sidebarSections = Array.from(sidebar.children);
+
+  const expandTooltip = new bootstrap.Tooltip(button, {
+    title: button.querySelector(".pst-expand-sidebar-label").textContent,
+
+    // In manual testing, relying on Bootstrap to handle "hover" and "focus" was buggy.
+    trigger: "manual",
+
+    placement: "left",
+    fallbackPlacements: ["right"],
+
+    // Offsetting the tooltip a bit more than the default [0, 0] solves an issue
+    // where the appearance of the tooltip triggers a mouseleave event which in
+    // turn triggers the call to hide the tooltip. So in certain areas around
+    // the button, it would appear to the user that tooltip flashes in and then
+    // back out.
+    offset: [0, 12],
+  });
+
+  const showTooltip = () => {
+    // Only show the "expand sidebar" tooltip when the sidebar is not expanded
+    if (button.getAttribute("aria-expanded") === "false") {
+      expandTooltip.show();
+    }
+  };
+  const hideTooltip = () => {
+    expandTooltip.hide();
+  };
+
+  function squeezeSidebar(prefersReducedMotion, done) {
+    // Before squeezing the sidebar, freeze the widths of its subsections.
+    // Otherwise, the subsections will also narrow and cause the text in the
+    // sidebar to reflow and wrap, which we don't want. This is necessary
+    // because we do not remove the sidebar contents from the layout (with
+    // `display: none`). Rather, we hide the contents from both sighted users
+    // and screen readers (with `visibility: hidden`). This provides better
+    // stability to the overall layout.
+    sidebarSections.forEach(
+      (el) => (el.style.width = el.getBoundingClientRect().width + "px"),
+    );
+
+    const afterSqueeze = () => {
+      // After squeezing the sidebar, set aria-expanded to false
+      button.setAttribute("aria-expanded", "false"); // "false" is in quotes because HTML attributes are strings
+
+      button.dataset.busy = false;
+    };
+
+    if (prefersReducedMotion) {
+      sidebar.classList.add("pst-squeeze");
+      afterSqueeze();
+    } else {
+      sidebar.addEventListener("transitionend", function onTransitionEnd() {
+        afterSqueeze();
+        sidebar.removeEventListener("transitionend", onTransitionEnd);
+      });
+      sidebar.classList.add("pst-squeeze");
+    }
+  }
+
+  function expandSidebar(prefersReducedMotion, done) {
+    hideTooltip();
+
+    const afterExpand = () => {
+      // After expanding the sidebar (which may be delayed by a CSS transition),
+      // unfreeze the widths of the subsections that were frozen when the sidebar
+      // was squeezed.
+      sidebarSections.forEach((el) => (el.style.width = null));
+
+      // After expanding the sidebar, set aria-expanded to "true" - in quotes
+      // because HTML attributes are strings.
+      button.setAttribute("aria-expanded", "true");
+
+      button.dataset.busy = false;
+    };
+
+    if (prefersReducedMotion) {
+      sidebar.classList.remove("pst-squeeze");
+      afterExpand();
+    } else {
+      sidebar.addEventListener("transitionend", function onTransitionEnd() {
+        afterExpand();
+        sidebar.removeEventListener("transitionend", onTransitionEnd);
+      });
+      sidebar.classList.remove("pst-squeeze");
+    }
+  }
+
+  button.addEventListener("click", () => {
+    if (button.dataset.busy === "true") {
+      return;
+    }
+    button.dataset.busy = "true";
+
+    const prefersReducedMotion = window.matchMedia(
+      "(prefers-reduced-motion)", // must be in parentheses
+    ).matches;
+
+    if (button.getAttribute("aria-expanded") === "true") {
+      squeezeSidebar(prefersReducedMotion);
+    } else {
+      expandSidebar(prefersReducedMotion);
+    }
+  });
+
+  button.addEventListener("focus", showTooltip);
+  button.addEventListener("mouseenter", showTooltip);
+  button.addEventListener("mouseleave", hideTooltip);
+  button.addEventListener("blur", hideTooltip);
+}
+
 /*******************************************************************************
  * Call functions after document loading.
  */
@@ -1026,6 +1149,15 @@ documentReady(addTOCInteractivity);
 documentReady(setupSearchButtons);
 documentReady(setupSearchAsYouType);
 documentReady(setupMobileSidebarKeyboardHandlers);
+documentReady(() => {
+  try {
+    setupCollapseSidebarButton();
+  } catch (err) {
+    // This exact error message is used in pytest tests
+    console.log("[PST] Error setting up collapse sidebar button");
+    console.error(err);
+  }
+});
 
 // Determining whether an element has scrollable content depends on stylesheets,
 // so we're checking for the "load" event rather than "DOMContentLoaded"
diff --git a/src/pydata_sphinx_theme/assets/styles/components/_sidebar-collapse.scss b/src/pydata_sphinx_theme/assets/styles/components/_sidebar-collapse.scss
new file mode 100644
index 0000000000..c6717df8e2
--- /dev/null
+++ b/src/pydata_sphinx_theme/assets/styles/components/_sidebar-collapse.scss
@@ -0,0 +1,178 @@
+/**
+ * The collapse/expand primary sidebar button
+ */
+
+.bd-sidebar-primary {
+  .sidebar-primary-item.pst-sidebar-collapse {
+    padding-top: 0;
+  }
+
+  #pst-collapse-sidebar-button {
+    // Only show this button when there's enough width for both sidebar and main
+    // content. Do not show the button in the mobile menu where it would not
+    // make any sense.
+    @include media-breakpoint-down($breakpoint-sidebar-primary) {
+      display: none;
+    }
+
+    border: 0; // reset
+    padding: 0; // reset
+    text-align: start; // reset;
+    background-color: transparent;
+    outline-offset: $focus-ring-offset;
+    display: flex;
+    flex-direction: row;
+    align-items: center;
+    gap: 0.25rem;
+
+    // min width and height of the button must be 24px to meet WCAG Success Criterion 2.5.8
+    min-width: 24px;
+    min-height: 24px;
+    position: relative;
+    bottom: 0.2em;
+
+    .pst-icon {
+      color: var(--pst-color-link);
+
+      // The padding value was chosen by trial and error. For reference, the
+      // svg-inline--fa class normally applies a -.125em adjustment but this
+      // adjustment doesn't work when the icon is within a flex box. Important:
+      // the padding top value must match the padding bottom value because the
+      // icon undergoes a 180deg rotation when the sidebar is collapsed.
+      padding: 0.4em 0;
+
+      // This value was also chosen by trial and error until it looked good.
+      height: 1.3em;
+    }
+
+    .pst-collapse-sidebar-label {
+      // // inline-flex so we can set dimensions (width, height)
+      // display: inline-flex;
+      width: 100%;
+      height: 100%;
+
+      @include link-style-default;
+    }
+
+    .pst-expand-sidebar-label {
+      // inline-flex so we can set dimensions (width, height)
+      // display: inline-flex;
+
+      // When the sidebar is squeezed, there is no space to show the "expand
+      // sidebar" label. However, the label text is copied to a Bootstrap
+      // tooltip. It's also exposed to screen readers with this
+      // `visually-hidden` mixin from Bootstrap.
+      @include visually-hidden;
+
+      // Turn off for screen readers initially because the sidebar starts off in the expanded state.
+      // When the
+      visibility: hidden;
+    }
+
+    &:hover {
+      .pst-icon {
+        color: var(--pst-color-link-hover);
+      }
+
+      .pst-collapse-sidebar-label {
+        @include link-style-hover;
+      }
+    }
+  }
+
+  // Define transitions (if the environment permits animation)
+  @media (prefers-reduced-motion: no-preference) {
+    $duration: 400ms;
+
+    transition: width $duration ease;
+
+    #pst-collapse-sidebar-button {
+      .pst-icon {
+        transition:
+          transform $duration ease,
+          padding $duration ease;
+      }
+    }
+
+    @each $selector,
+      $delay
+        in (
+          // When the sidebar is collapsing, we need to delay the transition of
+          // properties that make the elements invisible so the user can see the
+          // opacity transition from 1 to 0 first.
+          ".pst-squeeze": $duration,
+          // When the sidebar is expanding, it's the opposite: we need to transition
+          // the properties that make the elements visible immediately so the user
+          // can watch the opacity transition from 0 to 1.
+          ":not(.pst-squeeze)": "0s"
+        )
+    {
+      &#{$selector} {
+        .pst-collapse-sidebar-label {
+          transition:
+            opacity $duration linear,
+            visibility 0s linear $delay,
+            width 0s linear $delay,
+            height 0s linear $delay;
+        }
+
+        .sidebar-primary-item:not(.pst-sidebar-collapse) {
+          transition:
+            opacity $duration linear,
+            visibility 0s linear $delay;
+        }
+
+        // There is no need to transition any other properties on the expand
+        // label (width, height, opacity) because it is always visually hidden
+        // (i.e., width 0, height 0, etc), but toggles its availability to
+        // screen readers as the sidebar collapses or expands via the
+        // `visibility` property.
+        .pst-expand-sidebar-label {
+          transition: visibility 0s linear $delay;
+        }
+      }
+    }
+  }
+
+  // Why "squeeze" and not "collapse"? Bootstrap uses the class name `collapse`
+  // so it seemed best to avoid possible confusion. (Later the class name was
+  // prefixed with `pst-`.)
+  &.pst-squeeze {
+    width: 4rem;
+    overflow: hidden;
+
+    #pst-collapse-sidebar-button {
+      .pst-icon {
+        transform: translateX(0.25em) rotate(180deg);
+      }
+
+      .pst-collapse-sidebar-label {
+        opacity: 0;
+        visibility: hidden;
+        width: 0;
+        height: 0;
+      }
+
+      .pst-expand-sidebar-label {
+        visibility: visible;
+      }
+    }
+
+    .sidebar-primary-item:not(.pst-sidebar-collapse) {
+      opacity: 0;
+      visibility: hidden;
+    }
+  }
+
+  &:not(.pst-squeeze) {
+    // When the sidebar is expanded, hide the "Expand Sidebar" label.
+    .pst-expand-sidebar-label {
+      visibility: hidden;
+    }
+
+    // This block is shorter than its counterpart above because there's no need,
+    // for example, to explicitly set `visibility: visible` or `opacity: 1` on
+    // the collapse label and sidebar subsections because those are the default
+    // values.
+  }
+}
diff --git a/src/pydata_sphinx_theme/assets/styles/pydata-sphinx-theme.scss b/src/pydata_sphinx_theme/assets/styles/pydata-sphinx-theme.scss
index 967be8d437..bf4573aee2 100644
--- a/src/pydata_sphinx_theme/assets/styles/pydata-sphinx-theme.scss
+++ b/src/pydata_sphinx_theme/assets/styles/pydata-sphinx-theme.scss
@@ -49,6 +49,7 @@
 @import "./components/prev-next";
 @import "./components/search";
 @import "./components/searchbox";
+@import "./components/sidebar-collapse";
 @import "./components/switcher-theme";
 @import "./components/switcher-version";
 @import "./components/toc-inpage";
diff --git a/src/pydata_sphinx_theme/assets/styles/sections/_sidebar-primary.scss b/src/pydata_sphinx_theme/assets/styles/sections/_sidebar-primary.scss
index cc337d04e9..11965df470 100644
--- a/src/pydata_sphinx_theme/assets/styles/sections/_sidebar-primary.scss
+++ b/src/pydata_sphinx_theme/assets/styles/sections/_sidebar-primary.scss
@@ -16,10 +16,10 @@ $sidebar-padding-right: 1rem;
   @include make-col(3);
 
   // Borders padding and whitespace
-  padding: 2rem $sidebar-padding-right 1rem 1rem;
+  padding: $sidebar-padding-right;
   border-right: 1px solid var(--pst-color-border);
   background-color: var(--pst-color-background);
-  overflow-y: auto;
+  overflow: hidden auto;
   font-size: var(--pst-sidebar-font-size-mobile);
 
   @include media-breakpoint-up($breakpoint-sidebar-primary) {
diff --git a/src/pydata_sphinx_theme/locale/ca/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/ca/LC_MESSAGES/sphinx.po
index f643554537..d26b1a87e2 100644
--- a/src/pydata_sphinx_theme/locale/ca/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/ca/LC_MESSAGES/sphinx.po
@@ -17,11 +17,11 @@ msgstr "Fes clic per a desplegar"
 msgid "Click to collapse"
 msgstr "Fes clic per a replegar"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr "Salta al contingut principal"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr "Torna a l'inici"
 
@@ -110,6 +110,14 @@ msgstr "pàgina següent"
 msgid "next"
 msgstr "següent"
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/cs/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/cs/LC_MESSAGES/sphinx.po
index a5aac7c10d..55df855620 100644
--- a/src/pydata_sphinx_theme/locale/cs/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/cs/LC_MESSAGES/sphinx.po
@@ -14,11 +14,11 @@ msgstr ""
 msgid "Click to collapse"
 msgstr ""
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr "Přejít k hlavnímu obsahu"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr "Zpět na začátek"
 
@@ -107,6 +107,14 @@ msgstr "další stránka"
 msgid "next"
 msgstr "další"
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/de/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/de/LC_MESSAGES/sphinx.po
index 52a0edbe42..fae89ec41b 100644
--- a/src/pydata_sphinx_theme/locale/de/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/de/LC_MESSAGES/sphinx.po
@@ -17,11 +17,11 @@ msgstr "Zum Erweitern klicken"
 msgid "Click to collapse"
 msgstr "Zum Zuklappen klicken"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr "Zum Hauptinhalt springen"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr "Zurück zum Anfang"
 
@@ -110,6 +110,14 @@ msgstr "Nächste Seite"
 msgid "next"
 msgstr "weiter"
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/en/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/en/LC_MESSAGES/sphinx.po
index 9f6b3b01e4..3ce0dbd8bf 100644
--- a/src/pydata_sphinx_theme/locale/en/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/en/LC_MESSAGES/sphinx.po
@@ -14,11 +14,11 @@ msgstr ""
 msgid "Click to collapse"
 msgstr ""
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr ""
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr ""
 
@@ -107,6 +107,14 @@ msgstr ""
 msgid "next"
 msgstr ""
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/es/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/es/LC_MESSAGES/sphinx.po
index a8f632b5ce..5d42734916 100644
--- a/src/pydata_sphinx_theme/locale/es/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/es/LC_MESSAGES/sphinx.po
@@ -20,11 +20,11 @@ msgstr "Haga clic para ampliar"
 msgid "Click to collapse"
 msgstr "Haga clic para colapsar"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr "Saltar al contenido principal"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr "Volver arriba"
 
@@ -42,8 +42,7 @@ msgstr "Error"
 
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/search.html:9
 msgid "Please activate JavaScript to enable the search functionality."
-msgstr ""
-"Por favor, active JavaScript para habilitar la funcionalidad de búsqueda."
+msgstr "Por favor, active JavaScript para habilitar la funcionalidad de búsqueda."
 
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/breadcrumbs.html:6
 msgid "Breadcrumb"
@@ -114,6 +113,14 @@ msgstr "siguiente página"
 msgid "next"
 msgstr "siguiente"
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/fr/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/fr/LC_MESSAGES/sphinx.po
index af986777d7..dd5f8ac371 100644
--- a/src/pydata_sphinx_theme/locale/fr/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/fr/LC_MESSAGES/sphinx.po
@@ -18,11 +18,11 @@ msgstr "Cliquer pour développer"
 msgid "Click to collapse"
 msgstr "Cliquer pour réduire"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr "Passer au contenu principal"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr "Haut de page"
 
@@ -111,6 +111,14 @@ msgstr "page suivante"
 msgid "next"
 msgstr "suivante"
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/it/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/it/LC_MESSAGES/sphinx.po
index 9726470d44..9dcddb26da 100644
--- a/src/pydata_sphinx_theme/locale/it/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/it/LC_MESSAGES/sphinx.po
@@ -14,11 +14,11 @@ msgstr "Fai click per espandere"
 msgid "Click to collapse"
 msgstr "Fai click per nascondere"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr "Passa ai contenuti principali"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr "Torna in alto"
 
@@ -107,6 +107,14 @@ msgstr "pagina seguente"
 msgid "next"
 msgstr "seguente"
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/ja/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/ja/LC_MESSAGES/sphinx.po
index 051b4235aa..41b2b502e9 100644
--- a/src/pydata_sphinx_theme/locale/ja/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/ja/LC_MESSAGES/sphinx.po
@@ -16,11 +16,11 @@ msgstr "クリックして拡大"
 msgid "Click to collapse"
 msgstr "クリックして折りたたむ"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr "本文へスキップ"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr "トップに戻る"
 
@@ -109,6 +109,14 @@ msgstr "次ページ"
 msgid "next"
 msgstr "次"
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/ru/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/ru/LC_MESSAGES/sphinx.po
index c2cabbd402..8052a1e908 100644
--- a/src/pydata_sphinx_theme/locale/ru/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/ru/LC_MESSAGES/sphinx.po
@@ -14,11 +14,11 @@ msgstr ""
 msgid "Click to collapse"
 msgstr ""
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr "Перейти к основному содержанию"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr ""
 
@@ -107,6 +107,14 @@ msgstr "следующая страница"
 msgid "next"
 msgstr "далее"
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/sphinx.pot b/src/pydata_sphinx_theme/locale/sphinx.pot
index be78620811..73f137b2c9 100644
--- a/src/pydata_sphinx_theme/locale/sphinx.pot
+++ b/src/pydata_sphinx_theme/locale/sphinx.pot
@@ -26,11 +26,11 @@ msgstr ""
 msgid "Click to collapse"
 msgstr ""
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr ""
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr ""
 
@@ -119,6 +119,14 @@ msgstr ""
 msgid "next"
 msgstr ""
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/locale/zh/LC_MESSAGES/sphinx.po b/src/pydata_sphinx_theme/locale/zh/LC_MESSAGES/sphinx.po
index 88417a6410..4c0639c3d0 100644
--- a/src/pydata_sphinx_theme/locale/zh/LC_MESSAGES/sphinx.po
+++ b/src/pydata_sphinx_theme/locale/zh/LC_MESSAGES/sphinx.po
@@ -14,11 +14,11 @@ msgstr "展开"
 msgid "Click to collapse"
 msgstr "收缩"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:48
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:57
 msgid "Skip to main content"
 msgstr "跳转至主要内容"
 
-#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:60
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html:69
 msgid "Back to top"
 msgstr "回到顶部"
 
@@ -107,6 +107,14 @@ msgstr "下一页"
 msgid "next"
 msgstr "下一条"
 
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:6
+msgid "Collapse Sidebar"
+msgstr ""
+
+#: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html:11
+msgid "Expand Sidebar"
+msgstr ""
+
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:3
 #: src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-nav-bs.html:4
 msgid "Section Navigation"
diff --git a/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html b/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html
new file mode 100644
index 0000000000..47b9651398
--- /dev/null
+++ b/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/components/sidebar-collapse.html
@@ -0,0 +1,13 @@
+<button id="pst-collapse-sidebar-button" aria-expanded="true" aria-controls="pst-primary-sidebar">
+  {#- Even though this SVG is not a Font Awesome SVG, we use the `svg-inline--fa` class to apply some useful styles -#}
+  <svg class="pst-icon svg-inline--fa" role="img" aria-hidden="true" focusable="false" viewBox="0 0 16 16" xmlns="http://www.w3.org/2000/svg">
+    <path fill="currentColor" d="M3 15.5C2.36232 15.5 1.74874 15.2564 1.28478 14.8189C0.820828 14.3815 0.541576 13.7832 0.504167 13.1467L0.5 13L0.5 3C0.499965 2.36232 0.743605 1.74874 1.18107 1.28478C1.61854 0.820828 2.21676 0.541576 2.85333 0.504167L3 0.5L13 0.5C13.6377 0.499965 14.2513 0.743605 14.7152 1.18107C15.1792 1.61854 15.4584 2.21676 15.4958 2.85333L15.5 3L15.5 13C15.5 13.6377 15.2564 14.2513 14.8189 14.7152C14.3815 15.1792 13.7832 15.4584 13.1467 15.4958L13 15.5L3 15.5ZM3 13.8333L10.5 13.8333L10.5 2.16667L3 2.16667C2.79589 2.16669 2.59889 2.24163 2.44636 2.37726C2.29383 2.5129 2.19638 2.69979 2.1725 2.9025L2.16667 3L2.16667 13C2.16669 13.2041 2.24163 13.4011 2.37726 13.5536C2.5129 13.7062 2.69979 13.8036 2.9025 13.8275L3 13.8333ZM6.65583 10.325L6.5775 10.2558L4.91083 8.58917C4.76735 8.44567 4.68116 8.25476 4.66843 8.05223C4.65569 7.84971 4.71729 7.6495 4.84167 7.48917L4.91083 7.41083L6.5775 5.74417C6.72747 5.59471 6.9287 5.50794 7.14032 5.50148C7.35194 5.49502 7.55809 5.56935 7.7169 5.70937C7.8757 5.8494 7.97525 6.04463 7.99533 6.25539C8.01541 6.46616 7.95451 6.67667 7.825 6.84417L7.75583 6.9225L6.67917 8L7.75583 9.0775C7.89931 9.22099 7.98551 9.41191 7.99824 9.61443C8.01097 9.81695 7.94938 10.0172 7.825 10.1775L7.75583 10.2558C7.61234 10.3993 7.42142 10.4855 7.2189 10.4982C7.01638 10.511 6.81617 10.4494 6.65583 10.325Z"/>
+  </svg>
+  <span class="pst-collapse-sidebar-label">{{ _("Collapse Sidebar") }}</span>
+  <span class="pst-expand-sidebar-label">
+    {#- Careful: the contents of this span element are read by JavaScript and passed to the Bootstrap tooltip.
+      If you modify the markup within this tag, be sure that the tooltip on the expand sidebar button still works
+      and doesn't have any extraneous whitespace. -#}
+    {{- _("Expand Sidebar") -}}
+  </span>
+</button>
diff --git a/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html b/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html
index 2b286a6b2d..dfe8df443d 100644
--- a/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html
+++ b/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/layout.html
@@ -88,7 +88,7 @@
       {# Primary sidebar #}
       {# If we have no sidebar TOC, pop the TOC component from the sidebars list #}
       {% if suppress_sidebar_toctree(includehidden=theme_sidebar_includehidden | tobool) %}
-        {% set sidebars = sidebars | reject("in", "sidebar-nav-bs.html") | list %}
+        {% set sidebars = sidebars | reject("in", ["sidebar-collapse.html", "sidebar-nav-bs.html"]) | list %}
       {% endif %}
       <dialog id="pst-primary-sidebar-modal"></dialog>
       <div id="pst-primary-sidebar" class="bd-sidebar-primary bd-sidebar{% if not sidebars %} hide-on-wide{% endif %}">
diff --git a/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/sections/sidebar-primary.html b/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/sections/sidebar-primary.html
index 4b0cf62c11..745b1013d6 100644
--- a/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/sections/sidebar-primary.html
+++ b/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/sections/sidebar-primary.html
@@ -27,7 +27,7 @@
   {% if sidebars %}
     <div class="sidebar-primary-items__start sidebar-primary__section">
       {%- for sidebartemplate in sidebars %}
-        <div class="sidebar-primary-item">{%- include sidebartemplate %}</div>
+        <div class="sidebar-primary-item{% if sidebartemplate == 'sidebar-collapse.html' %} pst-sidebar-collapse{% endif %}">{%- include sidebartemplate %}</div>
       {%- endfor %}
     </div>
   {% endif %}
diff --git a/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/theme.conf b/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/theme.conf
index 111691ea22..30d18cc4ae 100644
--- a/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/theme.conf
+++ b/src/pydata_sphinx_theme/theme/pydata_sphinx_theme/theme.conf
@@ -4,7 +4,7 @@ inherit = basic
 # instead we manually link it in `webpack-macros.html`
 stylesheet = styles/pydata-sphinx-theme.css
 pygments_style = tango
-sidebars = sidebar-nav-bs.html
+sidebars = sidebar-collapse, sidebar-nav-bs
 
 [options]
 # General configuration
diff --git a/tests/sites/sidebars/conf.py b/tests/sites/sidebars/conf.py
index ff475aee22..becfdb45bb 100644
--- a/tests/sites/sidebars/conf.py
+++ b/tests/sites/sidebars/conf.py
@@ -11,3 +11,6 @@
 # -- General configuration ---------------------------------------------------
 
 html_theme = "pydata_sphinx_theme"
+html_sidebars = {
+    "section2/no-sidebar": [],  # Turn off primary/left sidebar
+}
diff --git a/tests/sites/sidebars/section2/index.rst b/tests/sites/sidebars/section2/index.rst
index 94ab69deb2..7e74909637 100644
--- a/tests/sites/sidebars/section2/index.rst
+++ b/tests/sites/sidebars/section2/index.rst
@@ -4,6 +4,7 @@ Section 2 index
 .. toctree::
 
    page1
+   no-sidebar
    https://google.com
 
 
diff --git a/tests/sites/sidebars/section2/no-sidebar.rst b/tests/sites/sidebars/section2/no-sidebar.rst
new file mode 100644
index 0000000000..b26a93c46c
--- /dev/null
+++ b/tests/sites/sidebars/section2/no-sidebar.rst
@@ -0,0 +1,16 @@
+No Primary Sidebar
+==================
+
+This test fixture page has been configured to not have a primary sidebar via conf.py:
+
+.. code-block:: python
+    :caption: conf.py
+
+    html_sidebars = {
+        "no-sidebar": []  # Turn off primary/left sidebar
+    }
+
+Yes secondary
+-------------
+
+It can have a secondary sidebar.
diff --git a/tests/test_playwright.py b/tests/test_playwright.py
index cfc89b9457..3727cd414c 100644
--- a/tests/test_playwright.py
+++ b/tests/test_playwright.py
@@ -18,7 +18,7 @@
 
 # Using importorskip to ensure these tests are only loaded if Playwright is installed.
 playwright = pytest.importorskip("playwright")
-from playwright.sync_api import Page, expect  # noqa: E402
+from playwright.sync_api import ConsoleMessage, Page, expect  # noqa: E402
 
 
 repo_path = Path(__file__).parents[1]
@@ -171,3 +171,142 @@ def check_breadcrumb_truncation():
         assert not _is_overflowing(el)
 
     _check_test_site(site_name, site_path, check_breadcrumb_truncation)
+
+
+# ----------------- Test functions: collapse primary sidebar button --------------------
+class TestCollapseSidebarButton:
+    """Group the tests for the collapse sidebar button."""
+
+    site_name = "sidebars"
+
+    def test_collapse_sidebar_button(
+        self, sphinx_build_factory: Callable, page: Page, url_base: str
+    ) -> None:
+        """Test basic functionality of the collapse sidebar button.
+
+        Clicking the button should collapse the sidebar. Clicking again should expand.
+        """
+        site_path = _build_test_site(
+            self.site_name, sphinx_build_factory=sphinx_build_factory
+        )
+        assert site_path is not None
+
+        def get_width(locator):
+            bbox = locator.bounding_box()
+            assert bbox is not None
+            return bbox["width"]
+
+        def check_collapse_expand():
+            page.goto(
+                urljoin(
+                    url_base, f"playwright_tests/{self.site_name}/section1/index.html"
+                )
+            )
+            sidebar = page.locator("#pst-primary-sidebar")
+            expanded_sidebar_width = get_width(sidebar)
+
+            # Before collapsing the sidebar, a link to another page should be visible
+            toc_link = sidebar.get_by_role("link", name="Section 1 page 1")
+            expect(toc_link).to_be_visible()
+
+            button = page.locator("#pst-collapse-sidebar-button")
+            expect(button).to_have_attribute("aria-expanded", "true")
+            expanded_button_width = get_width(button)
+
+            # Collapse the sidebar
+            button.click()
+
+            # Wait for the button have aria-expanded=false so we know the CSS
+            # transitions have finished
+            expect(button).to_have_attribute("aria-expanded", "false")
+
+            # After collapsing sidebar, the link to another page should NOT be visible
+            expect(toc_link).not_to_be_visible()
+
+            # But the button should still be visible though smaller
+            expect(button).to_be_visible()
+            assert get_width(button) < expanded_button_width
+
+            # After collapsing the sidebar, its width should be smaller than it
+            # was before collapse
+            assert get_width(sidebar) < expanded_sidebar_width
+
+            # Expand the sidebar
+            button.click()
+
+            # Wait for aria-expanded=true so we know CSS transitions have finished
+            expect(button).to_have_attribute("aria-expanded", "true")
+            expect(toc_link).to_be_visible()
+            assert get_width(sidebar) == expanded_sidebar_width
+            assert get_width(button) == expanded_button_width
+
+        _check_test_site(self.site_name, site_path, check_collapse_expand)
+
+    def test_collapse_sidebar_button_not_in_mobile(
+        self, sphinx_build_factory: Callable, page: Page, url_base: str
+    ) -> None:
+        """Collapse button should not appear in mobile sidebar."""
+        # Size viewport to mobile phone
+        page.set_viewport_size({"width": 400, "height": 900})
+
+        site_path = _build_test_site(
+            self.site_name, sphinx_build_factory=sphinx_build_factory
+        )
+        assert site_path is not None
+
+        def check_not_in_mobile():
+            page.goto(
+                urljoin(
+                    url_base, f"playwright_tests/{self.site_name}/section1/index.html"
+                )
+            )
+
+            dialog = page.locator("#pst-primary-sidebar-modal")
+            hamburger = page.get_by_role("button", name="Site navigation")
+            collapse_button = page.locator("#pst-collapse-sidebar-button")
+
+            expect(dialog).not_to_be_visible()
+            expect(collapse_button).not_to_be_visible()
+
+            # open the mobile menu
+            hamburger.click()
+
+            expect(dialog).to_be_visible()
+            expect(collapse_button).not_to_be_visible()
+
+        _check_test_site(self.site_name, site_path, check_not_in_mobile)
+
+    def test_no_collapse_sidebar_button(
+        self, sphinx_build_factory: Callable, page: Page, url_base: str
+    ) -> None:
+        """No sidebar -> no collapse button."""
+        site_path = _build_test_site(
+            self.site_name, sphinx_build_factory=sphinx_build_factory
+        )
+        assert site_path is not None
+
+        def check_console_msg(msg: ConsoleMessage):
+            if msg.text == "[PST] Error setting up collapse sidebar button":
+                pytest.fail("Error setting up collapse sidebar button")
+
+        page.on("console", check_console_msg)
+
+        def check_no_collapse_sidebar_button():
+            response = page.goto(
+                urljoin(
+                    url_base,
+                    f"playwright_tests/{self.site_name}/section2/no-sidebar.html",
+                )
+            )
+
+            # Need to check that the response is 200 and need to wait for the
+            # JavaScript to finish executing. Otherwise, if the page is a 404 or
+            # if the JavaScript hasn't finished loading, then the test will
+            # check for the button, not find it, and pass.
+            assert response is not None and response.status == 200
+            page.wait_for_load_state("load")
+
+            button = page.locator("#pst-collapse-sidebar-button")
+            expect(button).not_to_be_attached()
+
+        _check_test_site(self.site_name, site_path, check_no_collapse_sidebar_button)