diff --git a/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp b/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp
--- a/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/futures/futures.unique_future/wait_for.pass.cpp
@@ -52,9 +52,9 @@
     std::future<T> f = p.get_future();
     std::thread(func, std::move(p)).detach();
     assert(f.valid());
-    assert(f.wait_for(ms(300)) == std::future_status::timeout);
+    assert(f.wait_for(ms(50)) == std::future_status::timeout);
     assert(f.valid());
-    assert(f.wait_for(ms(300)) == std::future_status::ready);
+    assert(f.wait_for(ms(600)) == std::future_status::ready);
     assert(f.valid());
     Clock::time_point t0 = Clock::now();
     f.wait();