diff --git a/include/boost/unordered/unordered_flat_set.hpp b/include/boost/unordered/unordered_flat_set.hpp
new file mode 100644
index 00000000..ced04bfb
--- /dev/null
+++ b/include/boost/unordered/unordered_flat_set.hpp
@@ -0,0 +1,186 @@
+// Copyright (C) 2022 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_UNORDERED_FLAT_SET_HPP_INCLUDED
+#define BOOST_UNORDERED_UNORDERED_FLAT_SET_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/unordered/unordered_flat_set_fwd.hpp>
+#include <boost/unordered/detail/foa.hpp>
+
+#include <boost/core/allocator_access.hpp>
+
+#include <initializer_list>
+#include <iterator>
+#include <type_traits>
+#include <utility>
+
+namespace boost {
+  namespace unordered {
+    template <class Key, class Hash, class KeyEqual, class Allocator>
+    class unordered_flat_set
+    {
+      struct set_types
+      {
+        using key_type = Key;
+        using value_type = Key;
+        static Key const& extract(value_type const& key) { return key; }
+      };
+
+      using table_type = detail::foa::table<set_types, Hash, KeyEqual,
+        typename boost::allocator_rebind<Allocator,
+          typename set_types::value_type>::type>;
+
+      table_type table_;
+
+    public:
+      using key_type = Key;
+      using value_type = typename set_types::value_type;
+      using size_type = std::size_t;
+      using key_equal = KeyEqual;
+      using reference = value_type&;
+      using const_reference = value_type const&;
+      using iterator = typename table_type::iterator;
+      using const_iterator = typename table_type::const_iterator;
+
+      iterator begin() noexcept { return table_.begin(); }
+      const_iterator begin() const noexcept { return table_.begin(); }
+      const_iterator cbegin() const noexcept { return table_.cbegin(); }
+
+      iterator end() noexcept { return table_.end(); }
+      const_iterator end() const noexcept { return table_.end(); }
+      const_iterator cend() const noexcept { return table_.cend(); }
+
+      /// Capacity
+      ///
+
+      BOOST_ATTRIBUTE_NODISCARD bool empty() const noexcept
+      {
+        return table_.empty();
+      }
+
+      size_type size() const noexcept { return table_.size(); }
+
+      /// Modifiers
+      ///
+
+      void clear() noexcept { table_.clear(); }
+
+      std::pair<iterator, bool> insert(value_type const& value)
+      {
+        return table_.insert(value);
+      }
+
+      std::pair<iterator, bool> insert(value_type&& value)
+      {
+        return table_.insert(std::move(value));
+      }
+
+      iterator insert(const_iterator, value_type const& value)
+      {
+        return table_.insert(value).first;
+      }
+
+      iterator insert(const_iterator, value_type&& value)
+      {
+        return table_.insert(std::move(value)).first;
+      }
+
+      template <class ForwardIterator>
+      typename std::enable_if<
+        std::is_base_of<std::forward_iterator_tag, ForwardIterator>::value,
+        void>::type
+      insert(ForwardIterator first, ForwardIterator last)
+      {
+        auto const len = std::distance(first, last);
+        table_.reserve(len);
+        for (auto pos = first; pos != last; ++pos) {
+          table_.insert(*pos);
+        }
+      }
+
+      template <class InputIterator>
+      typename std::enable_if<
+        !std::is_base_of<std::forward_iterator_tag, InputIterator>::value,
+        void>::type
+      insert(InputIterator first, InputIterator last)
+      {
+        for (auto pos = first; pos != last; ++pos) {
+          table_.insert(*pos);
+        }
+      }
+
+      void insert(std::initializer_list<value_type> ilist)
+      {
+        this->insert(ilist.begin(), ilist.end());
+      }
+
+      template <class... Args> std::pair<iterator, bool> emplace(Args&&... args)
+      {
+        return table_.emplace(std::forward<Args>(args)...);
+      }
+
+      void erase(const_iterator pos) { return table_.erase(pos); }
+      size_type erase(key_type const& key) { return table_.erase(key); }
+
+      /// Lookup
+      ///
+
+      size_type count(key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        return pos != table_.end() ? 1 : 0;
+      }
+
+      iterator find(key_type const& key) { return table_.find(key); }
+
+      const_iterator find(key_type const& key) const
+      {
+        return table_.find(key);
+      }
+
+      std::pair<iterator, iterator> equal_range(key_type const& key)
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      std::pair<const_iterator, const_iterator> equal_range(
+        key_type const& key) const
+      {
+        auto pos = table_.find(key);
+        if (pos == table_.end()) {
+          return {pos, pos};
+        }
+
+        auto next = pos;
+        ++next;
+        return {pos, next};
+      }
+
+      size_type bucket_count() const noexcept { return table_.capacity(); }
+
+      float load_factor() const noexcept { return table_.load_factor(); }
+
+      float max_load_factor() const noexcept
+      {
+        return table_.max_load_factor();
+      }
+
+      key_equal key_eq() const { return table_.key_eq(); }
+    };
+  } // namespace unordered
+} // namespace boost
+
+#endif
diff --git a/include/boost/unordered/unordered_flat_set_fwd.hpp b/include/boost/unordered/unordered_flat_set_fwd.hpp
new file mode 100644
index 00000000..91550cc0
--- /dev/null
+++ b/include/boost/unordered/unordered_flat_set_fwd.hpp
@@ -0,0 +1,30 @@
+
+// Copyright (C) 2022 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_UNORDERED_FLAT_SET_FWD_HPP_INCLUDED
+#define BOOST_UNORDERED_FLAT_SET_FWD_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/functional/hash_fwd.hpp>
+#include <boost/unordered/detail/fwd.hpp>
+#include <functional>
+#include <memory>
+
+namespace boost {
+  namespace unordered {
+    template <class Key, class Hash = boost::hash<Key>,
+      class KeyEqual = std::equal_to<Key>,
+      class Allocator = std::allocator<Key> >
+    class unordered_flat_set;
+  }
+
+  using boost::unordered::unordered_flat_set;
+} // namespace boost
+
+#endif
diff --git a/include/boost/unordered_flat_set.hpp b/include/boost/unordered_flat_set.hpp
new file mode 100644
index 00000000..6e2067f8
--- /dev/null
+++ b/include/boost/unordered_flat_set.hpp
@@ -0,0 +1,18 @@
+
+// Copyright (C) 2022 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0. (See accompanying
+// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
+
+//  See http://www.boost.org/libs/unordered for documentation
+
+#ifndef BOOST_UNORDERED_FLAT_SET_HPP_INCLUDED
+#define BOOST_UNORDERED_FLAT_SET_HPP_INCLUDED
+
+#include <boost/config.hpp>
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#pragma once
+#endif
+
+#include <boost/unordered/unordered_flat_set.hpp>
+
+#endif // BOOST_UNORDERED_FLAT_SET_HPP_INCLUDED
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