diff --git a/libcxx/include/__memory_resource/synchronized_pool_resource.h b/libcxx/include/__memory_resource/synchronized_pool_resource.h
index 6384564afc917..bcc1ac4a172e3 100644
--- a/libcxx/include/__memory_resource/synchronized_pool_resource.h
+++ b/libcxx/include/__memory_resource/synchronized_pool_resource.h
@@ -10,10 +10,12 @@
 #define _LIBCPP___MEMORY_RESOURCE_SYNCHRONIZED_POOL_RESOURCE_H
 
 #include <__config>
+#include <__cstddef/size_t.h>
 #include <__memory_resource/memory_resource.h>
 #include <__memory_resource/pool_options.h>
 #include <__memory_resource/unsynchronized_pool_resource.h>
-#include <mutex>
+#include <__mutex/mutex.h>
+#include <__mutex/unique_lock.h>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
diff --git a/libcxx/include/future b/libcxx/include/future
index cbf3ed9346417..5b2e9eed88e35 100644
--- a/libcxx/include/future
+++ b/libcxx/include/future
@@ -368,6 +368,7 @@ template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;
 
 #  include <__assert>
 #  include <__chrono/duration.h>
+#  include <__chrono/steady_clock.h>
 #  include <__chrono/time_point.h>
 #  include <__condition_variable/condition_variable.h>
 #  include <__exception/exception_ptr.h>
@@ -381,6 +382,9 @@ template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;
 #  include <__memory/shared_count.h>
 #  include <__memory/unique_ptr.h>
 #  include <__memory/uses_allocator.h>
+#  include <__mutex/lock_guard.h>
+#  include <__mutex/mutex.h>
+#  include <__mutex/unique_lock.h>
 #  include <__system_error/error_category.h>
 #  include <__system_error/error_code.h>
 #  include <__system_error/error_condition.h>
@@ -390,14 +394,19 @@ template <class R, class Alloc> struct uses_allocator<packaged_task<R>, Alloc>;
 #  include <__type_traits/conditional.h>
 #  include <__type_traits/decay.h>
 #  include <__type_traits/enable_if.h>
+#  include <__type_traits/invoke.h>
+#  include <__type_traits/is_same.h>
+#  include <__type_traits/remove_cvref.h>
+#  include <__type_traits/remove_reference.h>
 #  include <__type_traits/strip_signature.h>
 #  include <__type_traits/underlying_type.h>
 #  include <__utility/auto_cast.h>
 #  include <__utility/forward.h>
 #  include <__utility/move.h>
-#  include <mutex>
+#  include <__utility/swap.h>
 #  include <new>
 #  include <stdexcept>
+#  include <tuple>
 #  include <version>
 
 #  if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
diff --git a/libcxx/include/memory_resource b/libcxx/include/memory_resource
index 7de69e67b7c06..e54b7e6e2473f 100644
--- a/libcxx/include/memory_resource
+++ b/libcxx/include/memory_resource
@@ -66,6 +66,10 @@ namespace std::pmr {
 #  pragma GCC system_header
 #endif
 
+#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER >= 17 && _LIBCPP_STD_VER <= 20
+#  include <mutex>
+#endif
+
 #if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
 #  include <stdexcept>
 #endif
diff --git a/libcxx/include/syncstream b/libcxx/include/syncstream
index 970706976e1ff..2699a4b3a6fbb 100644
--- a/libcxx/include/syncstream
+++ b/libcxx/include/syncstream
@@ -121,6 +121,7 @@ namespace std {
 
 #if _LIBCPP_HAS_LOCALIZATION
 
+#  include <__mutex/lock_guard.h>
 #  include <__utility/move.h>
 #  include <ios>
 #  include <iosfwd> // required for declaration of default arguments
@@ -129,7 +130,6 @@ namespace std {
 
 #  if _LIBCPP_HAS_THREADS
 #    include <map>
-#    include <mutex>
 #    include <shared_mutex>
 #  endif
 
diff --git a/libcxx/test/libcxx/transitive_includes/cxx23.csv b/libcxx/test/libcxx/transitive_includes/cxx23.csv
index a008b4d76edde..096c321672474 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx23.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx23.csv
@@ -465,7 +465,6 @@ future iosfwd
 future istream
 future limits
 future locale
-future mutex
 future new
 future ratio
 future sstream
@@ -692,11 +691,9 @@ memory_resource compare
 memory_resource cstdint
 memory_resource ctime
 memory_resource limits
-memory_resource mutex
 memory_resource new
 memory_resource ratio
 memory_resource tuple
-memory_resource typeinfo
 memory_resource version
 mutex cerrno
 mutex climits
@@ -1076,7 +1073,6 @@ syncstream iosfwd
 syncstream limits
 syncstream locale
 syncstream map
-syncstream mutex
 syncstream new
 syncstream optional
 syncstream ostream
diff --git a/libcxx/test/libcxx/transitive_includes/cxx26.csv b/libcxx/test/libcxx/transitive_includes/cxx26.csv
index d5321da32b3d4..74d912e5fe3a3 100644
--- a/libcxx/test/libcxx/transitive_includes/cxx26.csv
+++ b/libcxx/test/libcxx/transitive_includes/cxx26.csv
@@ -464,7 +464,6 @@ future iosfwd
 future istream
 future limits
 future locale
-future mutex
 future new
 future ratio
 future sstream
@@ -691,11 +690,9 @@ memory_resource compare
 memory_resource cstdint
 memory_resource ctime
 memory_resource limits
-memory_resource mutex
 memory_resource new
 memory_resource ratio
 memory_resource tuple
-memory_resource typeinfo
 memory_resource version
 mutex cerrno
 mutex climits
@@ -1075,7 +1072,6 @@ syncstream iosfwd
 syncstream limits
 syncstream locale
 syncstream map
-syncstream mutex
 syncstream new
 syncstream optional
 syncstream ostream