diff --git a/src/firefox/ffPage.ts b/src/firefox/ffPage.ts
index b6222b42a7..0af4ca27ea 100644
--- a/src/firefox/ffPage.ts
+++ b/src/firefox/ffPage.ts
@@ -35,6 +35,7 @@ import { selectors } from '../selectors';
 const UTILITY_WORLD_NAME = '__playwright_utility_world__';
 
 export class FFPage implements PageDelegate {
+  readonly cspErrorsAsynchronousForInlineScipts = true;
   readonly rawMouse: RawMouseImpl;
   readonly rawKeyboard: RawKeyboardImpl;
   readonly _session: FFSession;
diff --git a/src/frames.ts b/src/frames.ts
index 76b20b8c4b..0faf59d94d 100644
--- a/src/frames.ts
+++ b/src/frames.ts
@@ -571,12 +571,19 @@ export class Frame {
     return this._raceWithCSPError(async () => {
       if (url !== null)
         return (await context.evaluateHandleInternal(addScriptUrl, { url, type })).asElement()!;
+      let result;
       if (path !== null) {
         let contents = await util.promisify(fs.readFile)(path, 'utf8');
         contents += '//# sourceURL=' + path.replace(/\n/g, '');
-        return (await context.evaluateHandleInternal(addScriptContent, { content: contents, type })).asElement()!;
+        result = (await context.evaluateHandleInternal(addScriptContent, { content: contents, type })).asElement()!;
+      } else {
+        result = (await context.evaluateHandleInternal(addScriptContent, { content: content!, type })).asElement()!;
       }
-      return (await context.evaluateHandleInternal(addScriptContent, { content: content!, type })).asElement()!;
+      // Another round trip to the browser to ensure that we receive CSP error messages
+      // (if any) logged asynchronously in a separate task on the content main thread.
+      if (this._page._delegate.cspErrorsAsynchronousForInlineScipts)
+        await context.evaluateInternal(() => true);
+      return result;
     });
 
     async function addScriptUrl(options: { url: string, type: string }): Promise<HTMLElement> {
diff --git a/src/page.ts b/src/page.ts
index 4d0772e40a..080aa9c92b 100644
--- a/src/page.ts
+++ b/src/page.ts
@@ -75,6 +75,8 @@ export interface PageDelegate {
 
   // Work around Chrome's non-associated input and protocol.
   inputActionEpilogue(): Promise<void>;
+  // Work around for asynchronously dispatched CSP errors in Firefox.
+  readonly cspErrorsAsynchronousForInlineScipts?: boolean;
 }
 
 type PageState = {
diff --git a/test/page.spec.js b/test/page.spec.js
index 74b81ae138..9c2e858aca 100644
--- a/test/page.spec.js
+++ b/test/page.spec.js
@@ -650,7 +650,7 @@ describe('Page.addScriptTag', function() {
   });
 
   // Firefox fires onload for blocked script before it issues the CSP console error.
-  it.fail(FFOX)('should throw when added with content to the CSP page', async({page, server}) => {
+  it('should throw when added with content to the CSP page', async({page, server}) => {
     await page.goto(server.PREFIX + '/csp.html');
     let error = null;
     await page.addScriptTag({ content: 'window.__injected = 35;' }).catch(e => error = e);