diff --git a/libcxx/include/CMakeLists.txt b/libcxx/include/CMakeLists.txt
--- a/libcxx/include/CMakeLists.txt
+++ b/libcxx/include/CMakeLists.txt
@@ -27,6 +27,7 @@
   __algorithm/generate.h
   __algorithm/half_positive.h
   __algorithm/includes.h
+  __algorithm/in_in_result.h
   __algorithm/inplace_merge.h
   __algorithm/is_heap_until.h
   __algorithm/is_heap.h
diff --git a/libcxx/include/__algorithm/in_in_result.h b/libcxx/include/__algorithm/in_in_result.h
new file mode 100644
--- /dev/null
+++ b/libcxx/include/__algorithm/in_in_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_IN_RESULT_H
+#define _LIBCPP___ALGORITHM_IN_IN_RESULT_H
+
+#include <__config>
+#include <__concepts/convertible_to.h>
+#include <__utility/move.h>
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#ifndef _LIBCPP_HAS_NO_RANGES
+
+namespace ranges {
+template <class _I1, class _I2>
+struct in_in_result {
+  [[no_unique_address]] _I1 in1;
+  [[no_unique_address]] _I2 in2;
+
+  template <class _II1, class _II2>
+    requires convertible_to<const _I1&, _II1> && convertible_to<const _I2&, _II2>
+  constexpr operator in_in_result<_II1, _II2>() const & {
+    return {in1, in2};
+  }
+
+  template <class _II1, class _II2>
+    requires convertible_to<_I1, _II1> && convertible_to<_I2, _II2>
+  constexpr operator in_in_result<_II1, _II2>() && {
+    return {std::move(in1), std::move(in2)};
+  }
+};
+} // namespace ranges
+
+#endif // _LIBCPP_HAS_NO_RANGES
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___ALGORITHM_IN_IN_RESULT_H
diff --git a/libcxx/include/algorithm b/libcxx/include/algorithm
--- a/libcxx/include/algorithm
+++ b/libcxx/include/algorithm
@@ -17,6 +17,10 @@
 
 namespace std
 {
+namespace ranges {
+  template <class I1, class I2>
+    struct in_in_result; // since C++20
+}
 
 template <class InputIterator, class Predicate>
     constexpr bool     // constexpr in C++20
@@ -688,6 +692,7 @@
 #include <__algorithm/includes.h>
 #include <__algorithm/inplace_merge.h>
 #include <__algorithm/is_heap.h>
+#include <__algorithm/in_in_result.h>
 #include <__algorithm/is_heap_until.h>
 #include <__algorithm/is_partitioned.h>
 #include <__algorithm/is_permutation.h>
diff --git a/libcxx/include/module.modulemap b/libcxx/include/module.modulemap
--- a/libcxx/include/module.modulemap
+++ b/libcxx/include/module.modulemap
@@ -247,6 +247,7 @@
       module generate_n               { private header "__algorithm/generate_n.h" }
       module half_positive            { private header "__algorithm/half_positive.h" }
       module includes                 { private header "__algorithm/includes.h" }
+      module in_in_result             { private header "__algorithm/in_in_result.h" }
       module inplace_merge            { private header "__algorithm/inplace_merge.h" }
       module is_heap                  { private header "__algorithm/is_heap.h" }
       module is_heap_until            { private header "__algorithm/is_heap_until.h" }
diff --git a/libcxx/test/std/algorithms/algorithms.results/in_in_result.pass.cpp b/libcxx/test/std/algorithms/algorithms.results/in_in_result.pass.cpp
new file mode 100644
--- /dev/null
+++ b/libcxx/test/std/algorithms/algorithms.results/in_in_result.pass.cpp
@@ -0,0 +1,80 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+
+// template <class I1, class I2>
+// struct in_in_result;
+
+#include "__algorithm/in_in_result.h"
+#include <algorithm>
+#include <cassert>
+#include <type_traits>
+
+struct MoveOnly {
+  MoveOnly() = default;
+  MoveOnly(const MoveOnly&) = delete;
+  MoveOnly(MoveOnly&& o) { o.movedFrom = true; }
+
+  bool movedFrom = false;
+};
+
+template <class T>
+struct ConstructibleFrom {
+  ConstructibleFrom(T c) : content{c} {}
+  T content;
+};
+
+struct S2 {};
+
+struct A {
+  explicit A(int);
+};
+static_assert(!std::is_constructible_v<std::ranges::in_in_result<A, A>,
+                                       std::ranges::in_in_result<int, int>>);
+
+struct B {
+  B(const int&);
+  B(int&&);
+};
+static_assert(std::is_constructible_v<std::ranges::in_in_result<B, B>, std::ranges::in_in_result<int, int>>);
+static_assert(std::is_constructible_v<std::ranges::in_in_result<B, B>, std::ranges::in_in_result<int, int>&>);
+static_assert(std::is_constructible_v<std::ranges::in_in_result<B, B>, const std::ranges::in_in_result<int, int>>);
+static_assert(std::is_constructible_v<std::ranges::in_in_result<B, B>, const std::ranges::in_in_result<int, int>&>);
+
+struct C {
+  C(int&);
+};
+static_assert(!std::is_constructible_v<std::ranges::in_in_result<C, C>, std::ranges::in_in_result<int, int>&>);
+
+static_assert(std::is_convertible_v<         std::ranges::in_in_result<int, int>&, std::ranges::in_in_result<long, long>>);
+static_assert(!std::is_nothrow_convertible_v<std::ranges::in_in_result<int, int>&, std::ranges::in_in_result<long, long>>);
+static_assert(std::is_convertible_v<         const std::ranges::in_in_result<int, int>&, std::ranges::in_in_result<long, long>>);
+static_assert(!std::is_nothrow_convertible_v<const std::ranges::in_in_result<int, int>&, std::ranges::in_in_result<long, long>>);
+static_assert(std::is_convertible_v<         std::ranges::in_in_result<int, int>&&, std::ranges::in_in_result<long, long>>);
+static_assert(!std::is_nothrow_convertible_v<std::ranges::in_in_result<int, int>&&, std::ranges::in_in_result<long, long>>);
+static_assert(std::is_convertible_v<         const std::ranges::in_in_result<int, int>&&, std::ranges::in_in_result<long, long>>);
+static_assert(!std::is_nothrow_convertible_v<const std::ranges::in_in_result<int, int>&&, std::ranges::in_in_result<long, long>>);
+
+int main(int, char**) {
+  {
+    std::ranges::in_in_result<int, double> res{10L, 0.};
+    assert(res.in1 == 10);
+    assert(res.in2 == 0.);
+    std::ranges::in_in_result<ConstructibleFrom<int>, ConstructibleFrom<double>> res2 = res;
+    assert(res2.in1.content == 10);
+    assert(res2.in2.content == 0.);
+  }
+  {
+    std::ranges::in_in_result<MoveOnly, S2> res;
+    static_assert(sizeof(res) == sizeof(MoveOnly));
+    assert(!res.in1.movedFrom);
+    [[maybe_unused]] auto res2 = static_cast<std::ranges::in_in_result<MoveOnly, S2>>(std::move(res));
+    assert(res.in1.movedFrom);
+  }
+}