diff --git a/libcxx/include/__availability b/libcxx/include/__availability
--- a/libcxx/include/__availability
+++ b/libcxx/include/__availability
@@ -172,6 +172,9 @@
     // be avoided.
 // #   define _LIBCPP_HAS_NO_VERBOSE_ABORT_IN_LIBRARY
 
+    // This controls the availabilty of everything inside the std::pmr namespace introduced in P0220R1.
+#  define _LIBCPP_AVAILABILITY_MEMORY_RESOURCE
+
 #elif defined(__APPLE__)
 
 #   define _LIBCPP_AVAILABILITY_SHARED_MUTEX                                    \
@@ -273,6 +276,8 @@
 
 #   define _LIBCPP_HAS_NO_VERBOSE_ABORT_IN_LIBRARY
 
+#  define _LIBCPP_AVAILABILITY_MEMORY_RESOURCE __attribute__((__unavailable__))
+
 #else
 
 // ...New vendors can add availability markup here...
diff --git a/libcxx/include/__memory_resource/memory_resource.h b/libcxx/include/__memory_resource/memory_resource.h
--- a/libcxx/include/__memory_resource/memory_resource.h
+++ b/libcxx/include/__memory_resource/memory_resource.h
@@ -26,7 +26,7 @@
 
 _LIBCPP_DIAGNOSTIC_PUSH
 _LIBCPP_CLANG_DIAGNOSTIC_IGNORED("-Wweak-vtables") // TODO: move destructor into the dylib
-class _LIBCPP_TYPE_VIS memory_resource {
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_MEMORY_RESOURCE memory_resource {
   static const size_t __max_align = alignof(max_align_t);
 
 public:
@@ -51,23 +51,22 @@
 
 // [mem.res.eq]
 
-inline _LIBCPP_HIDE_FROM_ABI bool operator==(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
+_LIBCPP_AVAILABILITY_MEMORY_RESOURCE inline _LIBCPP_HIDE_FROM_ABI bool
+operator==(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
   return &__lhs == &__rhs || __lhs.is_equal(__rhs);
 }
 
-inline _LIBCPP_HIDE_FROM_ABI bool operator!=(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
+_LIBCPP_AVAILABILITY_MEMORY_RESOURCE inline _LIBCPP_HIDE_FROM_ABI bool
+operator!=(const memory_resource& __lhs, const memory_resource& __rhs) noexcept {
   return !(__lhs == __rhs);
 }
 
 // [mem.res.global]
 
-_LIBCPP_FUNC_VIS memory_resource* get_default_resource() noexcept;
-
-_LIBCPP_FUNC_VIS memory_resource* set_default_resource(memory_resource*) noexcept;
-
-_LIBCPP_FUNC_VIS memory_resource* new_delete_resource() noexcept;
-
-_LIBCPP_FUNC_VIS memory_resource* null_memory_resource() noexcept;
+_LIBCPP_AVAILABILITY_MEMORY_RESOURCE _LIBCPP_FUNC_VIS memory_resource* get_default_resource() noexcept;
+_LIBCPP_AVAILABILITY_MEMORY_RESOURCE _LIBCPP_FUNC_VIS memory_resource* set_default_resource(memory_resource*) noexcept;
+_LIBCPP_AVAILABILITY_MEMORY_RESOURCE _LIBCPP_FUNC_VIS memory_resource* new_delete_resource() noexcept;
+_LIBCPP_AVAILABILITY_MEMORY_RESOURCE _LIBCPP_FUNC_VIS memory_resource* null_memory_resource() noexcept;
 
 } // namespace pmr
 
diff --git a/libcxx/include/__memory_resource/monotonic_buffer_resource.h b/libcxx/include/__memory_resource/monotonic_buffer_resource.h
--- a/libcxx/include/__memory_resource/monotonic_buffer_resource.h
+++ b/libcxx/include/__memory_resource/monotonic_buffer_resource.h
@@ -26,7 +26,7 @@
 
 // [mem.res.monotonic.buffer]
 
-class _LIBCPP_TYPE_VIS monotonic_buffer_resource : public memory_resource {
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_MEMORY_RESOURCE monotonic_buffer_resource : public memory_resource {
   static const size_t __default_buffer_capacity  = 1024;
   static const size_t __default_buffer_alignment = 16;
 
diff --git a/libcxx/include/__memory_resource/polymorphic_allocator.h b/libcxx/include/__memory_resource/polymorphic_allocator.h
--- a/libcxx/include/__memory_resource/polymorphic_allocator.h
+++ b/libcxx/include/__memory_resource/polymorphic_allocator.h
@@ -34,7 +34,7 @@
 // [mem.poly.allocator.class]
 
 template <class _ValueType>
-class _LIBCPP_TEMPLATE_VIS polymorphic_allocator {
+class _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_MEMORY_RESOURCE polymorphic_allocator {
 public:
   using value_type = _ValueType;
 
diff --git a/libcxx/include/__memory_resource/synchronized_pool_resource.h b/libcxx/include/__memory_resource/synchronized_pool_resource.h
--- a/libcxx/include/__memory_resource/synchronized_pool_resource.h
+++ b/libcxx/include/__memory_resource/synchronized_pool_resource.h
@@ -30,7 +30,7 @@
 
 // [mem.res.pool.overview]
 
-class _LIBCPP_TYPE_VIS synchronized_pool_resource : public memory_resource {
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_MEMORY_RESOURCE synchronized_pool_resource : public memory_resource {
 public:
   _LIBCPP_HIDE_FROM_ABI synchronized_pool_resource(const pool_options& __opts, memory_resource* __upstream)
       : __unsync_(__opts, __upstream) {}
diff --git a/libcxx/include/__memory_resource/unsynchronized_pool_resource.h b/libcxx/include/__memory_resource/unsynchronized_pool_resource.h
--- a/libcxx/include/__memory_resource/unsynchronized_pool_resource.h
+++ b/libcxx/include/__memory_resource/unsynchronized_pool_resource.h
@@ -27,7 +27,7 @@
 
 // [mem.res.pool.overview]
 
-class _LIBCPP_TYPE_VIS unsynchronized_pool_resource : public memory_resource {
+class _LIBCPP_TYPE_VIS _LIBCPP_AVAILABILITY_MEMORY_RESOURCE unsynchronized_pool_resource : public memory_resource {
   class __fixed_pool;
 
   class __adhoc_pool {
diff --git a/libcxx/include/deque b/libcxx/include/deque
--- a/libcxx/include/deque
+++ b/libcxx/include/deque
@@ -2934,7 +2934,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _ValueT>
-using deque = std::deque<_ValueT, polymorphic_allocator<_ValueT>>;
+using deque = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::deque<_ValueT, polymorphic_allocator<_ValueT>>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
 #endif
diff --git a/libcxx/include/forward_list b/libcxx/include/forward_list
--- a/libcxx/include/forward_list
+++ b/libcxx/include/forward_list
@@ -1783,7 +1783,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _ValueT>
-using forward_list = std::forward_list<_ValueT, polymorphic_allocator<_ValueT>>;
+using forward_list = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::forward_list<_ValueT, polymorphic_allocator<_ValueT>>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
 #endif
diff --git a/libcxx/include/list b/libcxx/include/list
--- a/libcxx/include/list
+++ b/libcxx/include/list
@@ -2366,7 +2366,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _ValueT>
-using list = std::list<_ValueT, polymorphic_allocator<_ValueT>>;
+using list = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::list<_ValueT, polymorphic_allocator<_ValueT>>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
 #endif
diff --git a/libcxx/include/map b/libcxx/include/map
--- a/libcxx/include/map
+++ b/libcxx/include/map
@@ -2343,10 +2343,12 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _KeyT, class _ValueT, class _CompareT = std::less<_KeyT>>
-using map = std::map<_KeyT, _ValueT, _CompareT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;
+using map = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE
+    std::map<_KeyT, _ValueT, _CompareT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;
 
 template <class _KeyT, class _ValueT, class _CompareT = std::less<_KeyT>>
-using multimap = std::multimap<_KeyT, _ValueT, _CompareT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;
+using multimap = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE
+    std::multimap<_KeyT, _ValueT, _CompareT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
 #endif
diff --git a/libcxx/include/regex b/libcxx/include/regex
--- a/libcxx/include/regex
+++ b/libcxx/include/regex
@@ -6842,12 +6842,12 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _BidirT>
-using match_results = std::match_results<_BidirT, polymorphic_allocator<std::sub_match<_BidirT>>>;
+using match_results = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::match_results<_BidirT, polymorphic_allocator<std::sub_match<_BidirT>>>;
 
-using cmatch  = match_results<const char*>;
-using wcmatch = match_results<const wchar_t*>;
-using smatch  = match_results<std::pmr::string::const_iterator>;
-using wsmatch = match_results<std::pmr::wstring::const_iterator>;
+using cmatch  = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE match_results<const char*>;
+using wcmatch = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE match_results<const wchar_t*>;
+using smatch  = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE match_results<std::pmr::string::const_iterator>;
+using wsmatch = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE match_results<std::pmr::wstring::const_iterator>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
 #endif
diff --git a/libcxx/include/set b/libcxx/include/set
--- a/libcxx/include/set
+++ b/libcxx/include/set
@@ -1588,10 +1588,10 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _KeyT, class _CompareT = std::less<_KeyT>>
-using set = std::set<_KeyT, _CompareT, polymorphic_allocator<_KeyT>>;
+using set = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::set<_KeyT, _CompareT, polymorphic_allocator<_KeyT>>;
 
 template <class _KeyT, class _CompareT = std::less<_KeyT>>
-using multiset = std::multiset<_KeyT, _CompareT, polymorphic_allocator<_KeyT>>;
+using multiset = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::multiset<_KeyT, _CompareT, polymorphic_allocator<_KeyT>>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
 #endif
diff --git a/libcxx/include/string b/libcxx/include/string
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -4678,12 +4678,13 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _CharT, class _TraitsT = std::char_traits<_CharT>>
-using basic_string = std::basic_string<_CharT, _TraitsT, polymorphic_allocator<_CharT>>;
+using basic_string =
+    _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::basic_string<_CharT, _TraitsT, polymorphic_allocator<_CharT>>;
 
-using string    = basic_string<char>;
-using u16string = basic_string<char16_t>;
-using u32string = basic_string<char32_t>;
-using wstring   = basic_string<wchar_t>;
+using string    = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE basic_string<char>;
+using u16string = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE basic_string<char16_t>;
+using u32string = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE basic_string<char32_t>;
+using wstring   = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE basic_string<wchar_t>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
 #endif
diff --git a/libcxx/include/unordered_map b/libcxx/include/unordered_map
--- a/libcxx/include/unordered_map
+++ b/libcxx/include/unordered_map
@@ -2633,11 +2633,11 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _KeyT, class _ValueT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
-using unordered_map =
+using unordered_map = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE
     std::unordered_map<_KeyT, _ValueT, _HashT, _PredT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;
 
 template <class _KeyT, class _ValueT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
-using unordered_multimap =
+using unordered_multimap = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE
     std::unordered_multimap<_KeyT, _ValueT, _HashT, _PredT, polymorphic_allocator<std::pair<const _KeyT, _ValueT>>>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
diff --git a/libcxx/include/unordered_set b/libcxx/include/unordered_set
--- a/libcxx/include/unordered_set
+++ b/libcxx/include/unordered_set
@@ -1807,10 +1807,12 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _KeyT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
-using unordered_set = std::unordered_set<_KeyT, _HashT, _PredT, polymorphic_allocator<_KeyT>>;
+using unordered_set =
+    _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::unordered_set<_KeyT, _HashT, _PredT, polymorphic_allocator<_KeyT>>;
 
 template <class _KeyT, class _HashT = std::hash<_KeyT>, class _PredT = std::equal_to<_KeyT>>
-using unordered_multiset = std::unordered_multiset<_KeyT, _HashT, _PredT, polymorphic_allocator<_KeyT>>;
+using unordered_multiset =
+    _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::unordered_multiset<_KeyT, _HashT, _PredT, polymorphic_allocator<_KeyT>>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
 #endif
diff --git a/libcxx/include/vector b/libcxx/include/vector
--- a/libcxx/include/vector
+++ b/libcxx/include/vector
@@ -3272,7 +3272,7 @@
 _LIBCPP_BEGIN_NAMESPACE_STD
 namespace pmr {
 template <class _ValueT>
-using vector = std::vector<_ValueT, polymorphic_allocator<_ValueT>>;
+using vector = _LIBCPP_AVAILABILITY_MEMORY_RESOURCE std::vector<_ValueT, polymorphic_allocator<_ValueT>>;
 } // namespace pmr
 _LIBCPP_END_NAMESPACE_STD
 #endif
diff --git a/libcxx/test/libcxx/mem/mem.res/availability.verify.cpp b/libcxx/test/libcxx/mem/mem.res/availability.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/mem/mem.res/availability.verify.cpp
@@ -0,0 +1,58 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// UNSUPPORTED: c++03, c++11, c++14
+// REQUIRES: use_system_cxx_lib && (target={{.+}}-apple-macosx10.{{9|10|11|12|13|14|15}} || target={{.+}}-apple-macosx{{11.0|12.0}})
+
+#include <deque>
+#include <forward_list>
+#include <list>
+#include <map>
+#include <memory_resource>
+#include <regex>
+#include <set>
+#include <string>
+#include <unordered_map>
+#include <unordered_set>
+
+void f() {
+  [[maybe_unused]] std::pmr::match_results<const char8_t*> m1; // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::cmatch m2;                        // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::wcmatch m3;                       // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::smatch m4;                        // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::wsmatch m5;                       // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::deque<int> m6;                    // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::forward_list<int> m7;             // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::list<int> m8;                     // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::map<int, int> m9;                 // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::multimap<int, int> m10;           // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::set<int> m11;                     // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::multiset<int> m12;                // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::string m13;                       // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::wstring m14;                      // expected-error {{is unavailable}}
+  // TODO: check once alias is added
+  // [[maybe_unused]] std::pmr::u8string m15;                     // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::u16string m16;                    // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::u32string m17;                    // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::basic_string<char8_t> m18;        // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::unordered_map<int, int> m19;      // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::unordered_multimap<int, int> m20; // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::unordered_set<int, int> m21;      // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::unordered_multiset<int, int> m22; // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::vector<int> m23;                  // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::polymorphic_allocator<int> poly;  // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::memory_resource* res = nullptr;   // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::synchronized_pool_resource r1;    // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::monotonic_buffer_resource r2;     // expected-error {{is unavailable}}
+  [[maybe_unused]] std::pmr::unsynchronized_pool_resource r3;  // expected-error {{is unavailable}}
+  (void)std::pmr::get_default_resource();                      // expected-error {{is unavailable}}
+  (void)std::pmr::set_default_resource(nullptr);               // expected-error {{is unavailable}}
+  (void)std::pmr::new_delete_resource();                       // expected-error {{is unavailable}}
+  (void)std::pmr::null_memory_resource();                      // expected-error {{is unavailable}}
+  (void)(*res == *res);                                        // expected-error {{is unavailable}}
+}