diff --git a/changelog.d/19056.misc b/changelog.d/19056.misc
new file mode 100644
index 00000000000..f3a1b4e66ea
--- /dev/null
+++ b/changelog.d/19056.misc
@@ -0,0 +1 @@
+Move `oidc.load_metadata()` startup into `_base.start()`.
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index e5f4cfb0e6a..2de5bdb51e1 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -648,6 +648,16 @@ async def start(hs: "HomeServer", *, freeze: bool = True) -> None:
     # Apply the cache config.
     hs.config.caches.resize_all_caches()
 
+    # Load the OIDC provider metadatas, if OIDC is enabled.
+    if hs.config.oidc.oidc_enabled:
+        oidc = hs.get_oidc_handler()
+        # Loading the provider metadata also ensures the provider config is valid.
+        #
+        # FIXME: It feels a bit strange to validate and block on startup as one of these
+        # OIDC providers could be temporarily unavailable and cause Synapse to be unable
+        # to start.
+        await oidc.load_metadata()
+
     # Load the certificate from disk.
     refresh_certificate(hs)
 
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 3807a18ab75..fb937c63c11 100644
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -447,14 +447,6 @@ async def start(
             False otherwise the homeserver cannot be garbage collected after `shutdown`.
     """
 
-    # TODO: Feels like this should be moved somewhere else.
-    #
-    # Load the OIDC provider metadatas, if OIDC is enabled.
-    if hs.config.oidc.oidc_enabled:
-        oidc = hs.get_oidc_handler()
-        # Loading the provider metadata also ensures the provider config is valid.
-        await oidc.load_metadata()
-
     await _base.start(hs, freeze=freeze)
 
     # TODO: Feels like this should be moved somewhere else.