diff --git a/lib/test_runner/test_runner.test.ts b/lib/test_runner/test_runner.test.ts
index 0af61a5..37c2611 100644
--- a/lib/test_runner/test_runner.test.ts
+++ b/lib/test_runner/test_runner.test.ts
@@ -99,6 +99,31 @@ GokG
   );
 });
 
+Deno.test("only test definitions", async () => {
+  const context = getContext();
+  await assertRejects(
+    async () => {
+      await runTestDefinitions([{
+        name: "won't run",
+        fn: () => {
+          throw new Error("FAIL");
+        },
+      }, {
+        only: true,
+        name: "my test",
+        fn: () => {}, // pass
+      }], context);
+    },
+    Error,
+    "Exit code 1 thrown.",
+  );
+  wildcardAssertEquals(
+    context.output,
+    `test my test[WILDCARD]
+error: Test failed because the "only" option was used.\n`,
+  );
+});
+
 function getContext() {
   let output = "";
   return {
diff --git a/lib/test_runner/test_runner.ts b/lib/test_runner/test_runner.ts
index 847745d..9d2d159 100644
--- a/lib/test_runner/test_runner.ts
+++ b/lib/test_runner/test_runner.ts
@@ -23,6 +23,7 @@ export interface RunTestDefinitionsOptions {
 export interface TestDefinition {
   name: string;
   fn: (context: TestContext) => Promise<void> | void;
+  only?: boolean;
   ignore?: boolean;
 }
 
@@ -46,6 +47,10 @@ export async function runTestDefinitions(
   options: RunTestDefinitionsOptions,
 ) {
   const testFailures = [];
+  const hasOnly = testDefinitions.some((d) => d.only);
+  if (hasOnly) {
+    testDefinitions = testDefinitions.filter((d) => d.only);
+  }
   for (const definition of testDefinitions) {
     options.process.stdout.write("test " + definition.name + " ...");
     if (definition.ignore) {
@@ -87,6 +92,11 @@ export async function runTestDefinitions(
       );
     }
     options.process.exit(1);
+  } else if (hasOnly) {
+    options.process.stdout.write(
+      'error: Test failed because the "only" option was used.\n',
+    );
+    options.process.exit(1);
   }
 
   function getTestContext(