diff --git a/lib/assert.js b/lib/assert.js
index 2fc3cf33e80a18..9c900fcaf32055 100644
--- a/lib/assert.js
+++ b/lib/assert.js
@@ -451,8 +451,11 @@ async function waitForActual(block) {
   if (typeof block !== 'function') {
     throw new ERR_INVALID_ARG_TYPE('block', 'Function', block);
   }
+
+  // Return a rejected promise if `block` throws synchronously.
+  const resultPromise = block();
   try {
-    await block();
+    await resultPromise;
   } catch (e) {
     return e;
   }
diff --git a/test/parallel/test-assert-async.js b/test/parallel/test-assert-async.js
index ab03a53cd302c7..b6b744c9b1e3ae 100644
--- a/test/parallel/test-assert-async.js
+++ b/test/parallel/test-assert-async.js
@@ -13,7 +13,7 @@ common.crashOnUnhandledRejection();
 
 (async () => {
   await assert.rejects(
-    () => assert.fail(),
+    async () => assert.fail(),
     common.expectsError({
       code: 'ERR_ASSERTION',
       type: assert.AssertionError,
@@ -57,4 +57,17 @@ common.crashOnUnhandledRejection();
       }
     );
   }
+
+  {
+    const THROWN_ERROR = new Error();
+
+    await assert.rejects(() => {
+      throw THROWN_ERROR;
+    }).then(common.mustNotCall())
+      .catch(
+        common.mustCall((err) => {
+          assert.strictEqual(err, THROWN_ERROR);
+        })
+      );
+  }
 })().then(common.mustCall());