diff --git a/libcxx/include/fstream b/libcxx/include/fstream
--- a/libcxx/include/fstream
+++ b/libcxx/include/fstream
@@ -554,6 +554,18 @@
   case ios_base::in | ios_base::out | ios_base::app | ios_base::binary:
   case ios_base::in | ios_base::app | ios_base::binary:
     return "a+b" _LIBCPP_FOPEN_CLOEXEC_MODE;
+#if __cpp_lib_ios_noreplace >= 202207L
+  case ios_base::out | ios_base::noreplace:
+  case ios_base::out | ios_base::trunc | ios_base::noreplace:
+    return "wx" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:
+    return "w+x" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::out | ios_base::binary | ios_base::noreplace:
+  case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
+    return "wbx" _LIBCPP_FOPEN_CLOEXEC_MODE;
+  case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
+    return "w+bx" _LIBCPP_FOPEN_CLOEXEC_MODE;
+#endif
   default:
     return nullptr;
   }
@@ -667,6 +679,22 @@
         case ios_base::in | ios_base::app | ios_base::binary:
             __mdstr = L"a+b";
             break;
+#if __cpp_lib_ios_noreplace >= 202207L
+        case ios_base::out | ios_base::noreplace:
+        case ios_base::out | ios_base::trunc | ios_base::noreplace:
+            __mdstr = L"wx";
+            break;
+        case ios_base::in | ios_base::out | ios_base::trunc | ios_base::noreplace:
+            __mdstr = L"w+x";
+            break;
+        case ios_base::out | ios_base::binary | ios_base::noreplace:
+        case ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
+            __mdstr = L"wbx";
+            break;
+        case ios_base::in | ios_base::out | ios_base::trunc | ios_base::binary | ios_base::noreplace:
+            __mdstr = L"w+bx";
+            break;
+#endif
         default:
             __rt = nullptr;
             break;
diff --git a/libcxx/include/ios b/libcxx/include/ios
--- a/libcxx/include/ios
+++ b/libcxx/include/ios
@@ -58,6 +58,7 @@
     static constexpr openmode ate;
     static constexpr openmode binary;
     static constexpr openmode in;
+    static constexpr openmode noreplace;
     static constexpr openmode out;
     static constexpr openmode trunc;
 
@@ -272,12 +273,15 @@
     static const iostate goodbit = 0x0;
 
     typedef unsigned int openmode;
-    static const openmode app    = 0x01;
-    static const openmode ate    = 0x02;
-    static const openmode binary = 0x04;
-    static const openmode in     = 0x08;
-    static const openmode out    = 0x10;
-    static const openmode trunc  = 0x20;
+    static const openmode app       = 0x01;
+    static const openmode ate       = 0x02;
+    static const openmode binary    = 0x04;
+    static const openmode in        = 0x08;
+#if __cpp_lib_ios_noreplace >= 202207L
+    static const openmode noreplace = 0x40;
+#endif
+    static const openmode out       = 0x10;
+    static const openmode trunc     = 0x20;
 
     enum seekdir {beg, cur, end};
 
diff --git a/libcxx/include/version b/libcxx/include/version
--- a/libcxx/include/version
+++ b/libcxx/include/version
@@ -99,6 +99,7 @@
 __cpp_lib_interpolate                                   201902L <cmath> <numeric>
 __cpp_lib_invoke                                        201411L <functional>
 __cpp_lib_invoke_r                                      202106L <functional>
+__cpp_lib_ios_noreplace                                 202207L <ios>
 __cpp_lib_is_aggregate                                  201703L <type_traits>
 __cpp_lib_is_constant_evaluated                         201811L <type_traits>
 __cpp_lib_is_final                                      201402L <type_traits>
@@ -392,6 +393,7 @@
 // # define __cpp_lib_constexpr_typeinfo                   202106L
 # define __cpp_lib_forward_like                         202207L
 // # define __cpp_lib_invoke_r                             202106L
+# define __cpp_lib_ios_noreplace                        202207L
 # define __cpp_lib_is_scoped_enum                       202011L
 // # define __cpp_lib_move_only_function                   202110L
 # undef  __cpp_lib_optional
diff --git a/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/noreplace.pass.cpp b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/noreplace.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/input.output/file.streams/fstreams/fstream.cons/noreplace.pass.cpp
@@ -0,0 +1,73 @@
+//===----------------------------------------------------------------------===//
+//
+// 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, c++17, c++20
+// UNSUPPORTED: no-filesystem
+
+// Filesystem is supported on Apple platforms starting with macosx10.15.
+// UNSUPPORTED: use_system_cxx_lib && target={{.+}}-apple-macosx10.{{9|10|11|12|13|14}}
+
+// <fstream>
+
+// plate <class charT, class traits = char_traits<charT> >
+// class basic_fstream
+
+// explicit basic_fstream(const filesystem::path& s,
+//     ios_base::openmode mode = ios_base::in|ios_base::out);
+
+#include <fstream>
+#include <filesystem>
+#include <cassert>
+#include "test_macros.h"
+#include "platform_support.h"
+
+namespace fs = std::filesystem;
+
+int main(int, char**) {
+  fs::path p = get_temp_file_name();
+  {
+    std::fstream fs(
+        p.c_str(), std::ios_base::in | std::ios_base::out | std::ios_base::trunc | std::ios_base::noreplace);
+    assert(fs.rdstate() == std::ios_base::failbit);
+  }
+  std::remove(p.c_str());
+
+  {
+    std::fstream fs(
+        p.c_str(), std::ios_base::in | std::ios_base::out | std::ios_base::trunc | std::ios_base::noreplace);
+    double x = 0;
+    fs << 3.25;
+    fs.seekg(0);
+    fs >> x;
+    assert(x == 3.25);
+
+    fs.close();
+    std::fstream fs2(
+        p.c_str(), std::ios_base::in | std::ios_base::out | std::ios_base::trunc | std::ios_base::noreplace);
+    assert(fs2.rdstate() == std::ios_base::failbit);
+  }
+  std::remove(p.c_str());
+
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+  {
+    std::wfstream fs(
+        p.c_str(), std::ios_base::in | std::ios_base::out | std::ios_base::trunc | std::ios_base::noreplace);
+    double x = 0;
+    fs << 3.25;
+    fs.seekg(0);
+    fs >> x;
+    assert(x == 3.25);
+
+    fs.close();
+    std::wfstream fs2(
+        p.c_str(), std::ios_base::in | std::ios_base::out | std::ios_base::trunc | std::ios_base::noreplace);
+    assert(fs2.rdstate() == std::ios_base::failbit);
+  }
+  std::remove(p.c_str());
+#endif
+}
diff --git a/libcxx/utils/generate_feature_test_macro_components.py b/libcxx/utils/generate_feature_test_macro_components.py
--- a/libcxx/utils/generate_feature_test_macro_components.py
+++ b/libcxx/utils/generate_feature_test_macro_components.py
@@ -391,6 +391,10 @@
     "values": { "c++2b": 202106 },
     "headers": ["functional"],
     "unimplemented": True,
+  }, {
+    "name": "__cpp_lib_ios_noreplace",
+    "values": { "c++2b": 202207 },
+    "headers": ["ios"],
   }, {
     "name": "__cpp_lib_is_aggregate",
     "values": { "c++17": 201703 },