diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -26,6 +26,7 @@
   __algorithm/generate.h
   __algorithm/generate_n.h
   __algorithm/half_positive.h
+  __algorithm/in_fun_result.h
   __algorithm/in_in_result.h
   __algorithm/in_out_result.h
   __algorithm/includes.h
diff --git a/libcxx/include/__algorithm/in_fun_result.h b/libcxx/include/__algorithm/in_fun_result.h
new file mode 100644
--- /dev/null
+++ b/libcxx/include/__algorithm/in_fun_result.h
@@ -0,0 +1,45 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBCPP___ALGORITHM_IN_FUN_RESULT_H
+#define _LIBCPP___ALGORITHM_IN_FUN_RESULT_H
+
+#include <__concepts/convertible_to.h>
+#include <__config>
+#include <__utility/move.h>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_HAS_NO_RANGES
+
+namespace ranges {
+template <class _Ip, class _Fp>
+struct in_fun_result {
+  [[no_unique_address]] _Ip in;
+  [[no_unique_address]] _Fp fun;
+
+  template <class _I2, class _F2>
+    requires convertible_to<const _Ip&, _I2> && convertible_to<const _Fp&, _F2>
+  constexpr operator in_fun_result<_I2, _F2>() const & {
+    return {in, fun};
+  }
+
+  template <class _I2, class _F2>
+    requires convertible_to<_Ip, _I2> && convertible_to<_Fp, _F2>
+  constexpr operator in_fun_result<_I2, _F2>() && {
+    return {std::move(in), std::move(fun)};
+  }
+};
+} // namespace ranges
+
+#endif // _LIBCPP_HAS_NO_RANGES
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IN_FUN_RESULT_H
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -20,7 +20,10 @@
 
 namespace ranges {
   template <class I1, class I2>
-    struct in_in_result; // since C++20
+    struct in_in_result;  // since C++20
+
+  template <class I, class F>
+    struct in_fun_result; // since C++20
 }
 
 template <class InputIterator, class Predicate>
@@ -699,6 +702,7 @@
 #include <__algorithm/in_in_result.h>
 #include <__algorithm/in_out_result.h>
 #include <__algorithm/includes.h>
+#include <__algorithm/in_fun_result.h>
 #include <__algorithm/inplace_merge.h>
 #include <__algorithm/is_heap.h>
 #include <__algorithm/is_heap_until.h>
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -246,6 +246,7 @@
       module generate                 { private header "__algorithm/generate.h" }
       module generate_n               { private header "__algorithm/generate_n.h" }
       module half_positive            { private header "__algorithm/half_positive.h" }
+      module in_fun_result            { private header "__algorithm/in_fun_result.h" }
       module in_in_result             { private header "__algorithm/in_in_result.h" }
       module in_out_result            { private header "__algorithm/in_out_result.h" }
       module includes                 { private header "__algorithm/includes.h" }
diff --git a/libcxx/test/libcxx/diagnostics/detail.headers/algorithm/in_fun_result.module.verify.cpp b/libcxx/test/libcxx/diagnostics/detail.headers/algorithm/in_fun_result.module.verify.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/libcxx/diagnostics/detail.headers/algorithm/in_fun_result.module.verify.cpp
@@ -0,0 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: modules-build
+
+// WARNING: This test was generated by 'generate_private_header_tests.py'
+// and should not be edited manually.
+
+// expected-error@*:* {{use of private header from outside its module: '__algorithm/in_fun_result.h'}}
+#include <__algorithm/in_fun_result.h>
diff --git a/libcxx/test/std/algorithms/algorithms.results/in_fun_result.pass.cpp b/libcxx/test/std/algorithms/algorithms.results/in_fun_result.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/algorithms/algorithms.results/in_fun_result.pass.cpp
@@ -0,0 +1,81 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+// UNSUPPORTED: libcpp-no-concepts
+// UNSUPPORTED: libcpp-has-no-incomplete-ranges
+
+// template <class I1, class I2>
+// struct in_fun_result;
+
+#include <algorithm>
+#include <cassert>
+#include <type_traits>
+
+#include "MoveOnly.h"
+
+template <class T>
+struct ConstructibleFrom {
+  constexpr ConstructibleFrom(T c) : content{c} {}
+  T content;
+};
+
+struct Empty {};
+
+struct A {
+  explicit A(int);
+};
+static_assert(!std::is_constructible_v<std::ranges::in_fun_result<A, A>,
+                                       std::ranges::in_fun_result<int, int>>);
+
+struct B {
+  B(const int&);
+  B(int&&);
+};
+static_assert(std::is_constructible_v<std::ranges::in_fun_result<B, B>, std::ranges::in_fun_result<int, int>>);
+static_assert(std::is_constructible_v<std::ranges::in_fun_result<B, B>, std::ranges::in_fun_result<int, int>&>);
+static_assert(std::is_constructible_v<std::ranges::in_fun_result<B, B>, const std::ranges::in_fun_result<int, int>>);
+static_assert(std::is_constructible_v<std::ranges::in_fun_result<B, B>, const std::ranges::in_fun_result<int, int>&>);
+
+struct C {
+  C(int&);
+};
+static_assert(!std::is_constructible_v<std::ranges::in_fun_result<C, C>, std::ranges::in_fun_result<int, int>&>);
+
+static_assert(std::is_convertible_v<         std::ranges::in_fun_result<int, int>&, std::ranges::in_fun_result<long, long>>);
+static_assert(!std::is_nothrow_convertible_v<std::ranges::in_fun_result<int, int>&, std::ranges::in_fun_result<long, long>>);
+static_assert(std::is_convertible_v<         const std::ranges::in_fun_result<int, int>&, std::ranges::in_fun_result<long, long>>);
+static_assert(!std::is_nothrow_convertible_v<const std::ranges::in_fun_result<int, int>&, std::ranges::in_fun_result<long, long>>);
+static_assert(std::is_convertible_v<         std::ranges::in_fun_result<int, int>&&, std::ranges::in_fun_result<long, long>>);
+static_assert(!std::is_nothrow_convertible_v<std::ranges::in_fun_result<int, int>&&, std::ranges::in_fun_result<long, long>>);
+static_assert(std::is_convertible_v<         const std::ranges::in_fun_result<int, int>&&, std::ranges::in_fun_result<long, long>>);
+static_assert(!std::is_nothrow_convertible_v<const std::ranges::in_fun_result<int, int>&&, std::ranges::in_fun_result<long, long>>);
+
+constexpr bool test() {
+  {
+    std::ranges::in_fun_result<int, double> res{10L, 0.};
+    assert(res.in == 10);
+    assert(res.fun == 0.);
+    std::ranges::in_fun_result<ConstructibleFrom<int>, ConstructibleFrom<double>> res2 = res;
+    assert(res2.in.content == 10);
+    assert(res2.fun.content == 0.);
+  }
+  {
+    std::ranges::in_fun_result<MoveOnly, Empty> res;
+    assert(res.in.get() == 1);
+    [[maybe_unused]] auto res2 = static_cast<std::ranges::in_fun_result<MoveOnly, Empty>>(std::move(res));
+    assert(res.in.get() == 0);
+  }
+
+  return true;
+}
+
+int main(int, char**) {
+  test();
+  static_assert(test());
+}
diff --git a/libcxx/test/std/algorithms/algorithms.results/no_unique_address.compile.pass.cpp b/libcxx/test/std/algorithms/algorithms.results/no_unique_address.compile.pass.cpp
--- a/libcxx/test/std/algorithms/algorithms.results/no_unique_address.compile.pass.cpp
+++ b/libcxx/test/std/algorithms/algorithms.results/no_unique_address.compile.pass.cpp
@@ -25,3 +25,7 @@
 static_assert(sizeof(std::ranges::in_in_result<Empty, int>) == sizeof(int));
 static_assert(sizeof(std::ranges::in_in_result<int, Empty>) == sizeof(int));
 static_assert(sizeof(std::ranges::in_in_result<Empty, Empty>) == 2 * sizeof(Empty));
+
+static_assert(sizeof(std::ranges::in_fun_result<Empty, int>) == sizeof(int));
+static_assert(sizeof(std::ranges::in_fun_result<int, Empty>) == sizeof(int));
+static_assert(sizeof(std::ranges::in_fun_result<Empty, Empty>) == 2 * sizeof(Empty));