diff --git a/libcxx/docs/ReleaseNotes.rst b/libcxx/docs/ReleaseNotes.rst
--- a/libcxx/docs/ReleaseNotes.rst
+++ b/libcxx/docs/ReleaseNotes.rst
@@ -47,6 +47,7 @@
 - N4190 (Removing auto_ptr, random_shuffle(), And Old <functional> Stuff)
 - P0154R1 (Hardware inference size)
 - P0618R0 (Deprecating <codecvt>)
+- LWG3659 (Consider ``ATOMIC_FLAG_INIT`` undeprecation)
 
 - Marked the following papers as "Complete" (note that some of those might have
   been implemented in a previous release but not marked as such):
diff --git a/libcxx/docs/Status/Cxx2bIssues.csv b/libcxx/docs/Status/Cxx2bIssues.csv
--- a/libcxx/docs/Status/Cxx2bIssues.csv
+++ b/libcxx/docs/Status/Cxx2bIssues.csv
@@ -156,6 +156,7 @@
 "`3650 <https://wg21.link/LWG3650>`__","Are ``std::basic_string`` 's ``iterator`` and ``const_iterator`` constexpr iterators?","February 2022","|Nothing to do|",""
 "`3654 <https://wg21.link/LWG3654>`__","``basic_format_context::arg(size_t)`` should be ``noexcept`` ","February 2022","|Complete|","15.0","|format|"
 "`3657 <https://wg21.link/LWG3657>`__","``std::hash<std::filesystem::path>`` is not enabled","February 2022","",""
+"`3657 <https://wg21.link/LWG3659>`__","Consider ``ATOMIC_FLAG_INIT`` undeprecation","February 2022","|Complete|","15.0"
 "`3660 <https://wg21.link/LWG3660>`__","``iterator_traits<common_iterator>::pointer`` should conform to §[iterator.traits]","February 2022","|Complete|","14.0"
 "`3661 <https://wg21.link/LWG3661>`__","``constinit atomic<shared_ptr<T>> a(nullptr);`` should work","February 2022","",""
 "","","","",""
diff --git a/libcxx/include/atomic b/libcxx/include/atomic
--- a/libcxx/include/atomic
+++ b/libcxx/include/atomic
@@ -2696,7 +2696,6 @@
 
 #if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
 # if defined(_LIBCPP_CLANG_VER) && _LIBCPP_CLANG_VER >= 1400
-#  pragma clang deprecated(ATOMIC_FLAG_INIT)
 #  pragma clang deprecated(ATOMIC_VAR_INIT)
 # endif
 #endif // _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_DISABLE_DEPRECATION_WARNINGS)
diff --git a/libcxx/test/std/atomics/atomics.flag/init.pass.cpp b/libcxx/test/std/atomics/atomics.flag/init.pass.cpp
--- a/libcxx/test/std/atomics/atomics.flag/init.pass.cpp
+++ b/libcxx/test/std/atomics/atomics.flag/init.pass.cpp
@@ -7,7 +7,6 @@
 //===----------------------------------------------------------------------===//
 
 // XFAIL: c++03
-// ADDITIONAL_COMPILE_FLAGS: -D_LIBCPP_DISABLE_DEPRECATION_WARNINGS
 
 // <atomic>