diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp
index ca48eee19d27..8aa233f66b5a 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvar/wait_for.pass.cpp
@@ -9,6 +9,8 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 
+// FLAKY_TEST
+
 // <condition_variable>
 
 // class condition_variable;
diff --git a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp
index 98f6c432c977..16e6ff9f105b 100644
--- a/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp
+++ b/libcxx/test/std/thread/thread.condition/thread.condition.condvarany/notify_one.pass.cpp
@@ -9,6 +9,8 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 
+// FLAKY_TEST
+
 // <condition_variable>
 
 // class condition_variable_any;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp
index 7f89f0af801f..694e311b7bfb 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.cons/mutex_try_to_lock.pass.cpp
@@ -10,6 +10,8 @@
 // UNSUPPORTED: libcpp-has-no-threads
 // UNSUPPORTED: c++98, c++03, c++11
 
+// FLAKY_TEST
+
 // <shared_mutex>
 
 // template <class Mutex> class shared_lock;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp
index dcfdfd11a7e1..f63256373b27 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.cons/mutex.pass.cpp
@@ -9,6 +9,8 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 
+// FLAKY_TEST
+
 // <mutex>
 
 // template <class Mutex> class unique_lock;
diff --git a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp
index cb5c55925eef..ebaf3e6deb23 100644
--- a/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp
+++ b/libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.unique/thread.lock.unique.locking/lock.pass.cpp
@@ -9,6 +9,8 @@
 //
 // UNSUPPORTED: libcpp-has-no-threads
 
+// FLAKY_TEST
+
 // <mutex>
 
 // template <class Mutex> class unique_lock;