diff --git a/packages/wxt/src/core/utils/__tests__/manifest.test.ts b/packages/wxt/src/core/utils/__tests__/manifest.test.ts
index 5775be31c..7c7f4c03f 100644
--- a/packages/wxt/src/core/utils/__tests__/manifest.test.ts
+++ b/packages/wxt/src/core/utils/__tests__/manifest.test.ts
@@ -107,6 +107,30 @@ describe('Manifest Utils', () => {
         },
       );
 
+      it('should allow converting action to page_action for Firefox MV3', async () => {
+        const popup = popupEntrypoint('page_action');
+        const buildOutput = fakeBuildOutput();
+        setFakeWxt({
+          config: {
+            manifestVersion: 3,
+            outDir,
+            browser: 'firefox',
+          },
+        });
+        const expected = {
+          default_icon: popup.options.defaultIcon,
+          default_title: popup.options.defaultTitle,
+          default_popup: 'popup.html',
+        };
+
+        const { manifest: actual } = await generateManifest(
+          [popup],
+          buildOutput,
+        );
+
+        expect(actual.page_action).toEqual(expected);
+      });
+
       it('should include default_area for Firefox in mv3', async () => {
         const popup = fakePopupEntrypoint({
           options: {
@@ -1464,7 +1488,11 @@ describe('Manifest Utils', () => {
         ['chrome', 2, { ...mv2Manifest, ...hostPermissionsManifest }],
         ['safari', 2, { ...mv2Manifest, ...hostPermissionsManifest }],
         ['edge', 2, { ...mv2Manifest, ...hostPermissionsManifest }],
-        ['firefox', 3, { ...mv3Manifest, ...hostPermissionsManifest }],
+        [
+          'firefox',
+          3,
+          { ...mv3Manifest, ...hostPermissionsManifest, page_action: {} },
+        ],
         ['chrome', 3, { ...mv3Manifest, ...hostPermissionsManifest }],
         ['safari', 3, { ...mv3Manifest, ...hostPermissionsManifest }],
         ['edge', 3, { ...mv3Manifest, ...hostPermissionsManifest }],
diff --git a/packages/wxt/src/core/utils/manifest.ts b/packages/wxt/src/core/utils/manifest.ts
index a0e3b0592..e93498607 100644
--- a/packages/wxt/src/core/utils/manifest.ts
+++ b/packages/wxt/src/core/utils/manifest.ts
@@ -284,20 +284,19 @@ function addEntrypoints(
     if (popup.options.themeIcons)
       // @ts-expect-error: Not typed by @wxt-dev/browser, but supported by Firefox
       options.theme_icons = popup.options.themeIcons;
-    if (manifest.manifest_version === 3) {
-      manifest.action = {
-        ...manifest.action,
-        ...options,
-        default_popup,
-      };
-    } else {
-      const key = popup.options.mv2Key ?? 'browser_action';
-      manifest[key] = {
-        ...manifest[key],
-        ...options,
-        default_popup,
-      };
-    }
+
+    const actionKey =
+      manifest.manifest_version === 2
+        ? (popup.options.mv2Key ?? 'browser_action')
+        : wxt.config.browser === 'firefox'
+          ? (popup.options.mv2Key ?? 'action')
+          : 'action';
+
+    manifest[actionKey] = {
+      ...manifest[actionKey],
+      ...options,
+      default_popup,
+    };
   }
 
   if (devtools) {
@@ -699,6 +698,8 @@ function stripKeys(manifest: Browser.runtime.Manifest): void {
       keysToRemove.push(...firefoxMv3OnlyKeys);
   } else {
     keysToRemove.push(...mv2OnlyKeys);
+    if (wxt.config.browser !== 'firefox')
+      keysToRemove.push(...chromeMv2OnlyKeys);
   }
 
   keysToRemove.forEach((key) => {
@@ -707,7 +708,6 @@ function stripKeys(manifest: Browser.runtime.Manifest): void {
 }
 
 const mv2OnlyKeys = [
-  'page_action',
   'browser_action',
   'automation',
   'content_capabilities',
@@ -732,6 +732,7 @@ const mv3OnlyKeys = [
   'optional_host_permissions',
   'side_panel',
 ];
+const chromeMv2OnlyKeys = ['page_action'];
 const firefoxMv3OnlyKeys = ['host_permissions'];
 
 const DEFAULT_MV3_EXTENSION_PAGES_CSP =
diff --git a/packages/wxt/src/types.ts b/packages/wxt/src/types.ts
index 9a9723a3f..e903e90be 100644
--- a/packages/wxt/src/types.ts
+++ b/packages/wxt/src/types.ts
@@ -721,7 +721,13 @@ export interface ThemeIcon {
 }
 
 export interface PopupEntrypointOptions extends BaseEntrypointOptions {
-  /** Defaults to "browser_action" to be equivalent to MV3's "action" key */
+  /**
+   * Defaults to "browser_action" to be equivalent to MV3's "action" key.
+   *
+   * This option name is bad - it is also respected for Firefox MV3 (though
+   * `browser_action` is converted to `action`) to allow using a `page_action`
+   * in MV3.
+   */
   mv2Key?: PerBrowserOption<'browser_action' | 'page_action'>;
   defaultIcon?: Record<string, string>;
   defaultTitle?: PerBrowserOption<string>;