diff --git a/xpcom/tests/gtest/TestThreadPool.cpp b/xpcom/tests/gtest/TestThreadPool.cpp
index 4b3f81d2f8d9..4ade063034b1 100644
--- a/xpcom/tests/gtest/TestThreadPool.cpp
+++ b/xpcom/tests/gtest/TestThreadPool.cpp
@@ -134,8 +134,8 @@ TEST(ThreadPool, ShutdownWithTimeout)
     pool->Dispatch(task, NS_DISPATCH_NORMAL);
   }
 
-  // Wait for a max of 300 ms. All threads should be done by then.
-  pool->ShutdownWithTimeout(300);
+  // Wait for a max of 350 ms. All threads should be done by then.
+  pool->ShutdownWithTimeout(350);
   EXPECT_EQ(allThreadsCount, 4);
 
   Atomic<int> infiniteLoopCount(0);
@@ -195,9 +195,9 @@ TEST(ThreadPool, ShutdownWithTimeoutThenSleep)
           }),
       NS_DISPATCH_NORMAL);
 
-  // Wait for a max of 300 ms. The thread should still be sleeping, and will
+  // Wait for a max of 350 ms. The thread should still be sleeping, and will
   // be leaked.
-  pool->ShutdownWithTimeout(300);
+  pool->ShutdownWithTimeout(350);
   // We can't be exact here; the thread we're running on might have gotten
   // suspended and the sleeping thread, above, might have finished.
   EXPECT_GE(count, 3);