diff --git a/include/boost/unordered/detail/implementation.hpp b/include/boost/unordered/detail/implementation.hpp
index 4d411b31..7c9150ba 100644
--- a/include/boost/unordered/detail/implementation.hpp
+++ b/include/boost/unordered/detail/implementation.hpp
@@ -40,6 +40,7 @@
 #include <boost/type_traits/is_nothrow_move_constructible.hpp>
 #include <boost/type_traits/is_nothrow_swappable.hpp>
 #include <boost/type_traits/is_same.hpp>
+#include <boost/type_traits/make_void.hpp>
 #include <boost/type_traits/remove_const.hpp>
 #include <boost/unordered/detail/fwd.hpp>
 #include <boost/utility/addressof.hpp>
@@ -722,6 +723,22 @@ namespace boost {
 
 #endif
 
+////////////////////////////////////////////////////////////////////////////
+// Type checkers used for the transparent member functions added by C++20 and up
+
+      template <class>
+      struct make_dependent : public true_type {};
+
+      template <class, class = void> struct is_transparent : public false_type
+      {
+      };
+
+      template <class T>
+      struct is_transparent<T,
+        typename boost::make_void<typename T::is_transparent>::type> : public true_type
+      {
+      };
+
 ////////////////////////////////////////////////////////////////////////////
 // Explicitly call a destructor
 
diff --git a/include/boost/unordered/unordered_map.hpp b/include/boost/unordered/unordered_map.hpp
index aed6619b..7e6dd467 100644
--- a/include/boost/unordered/unordered_map.hpp
+++ b/include/boost/unordered/unordered_map.hpp
@@ -757,7 +757,12 @@ namespace boost {
 
       size_type count(const key_type&) const;
 
-      template <class TransparentKey> size_type count(const TransparentKey&) const;
+      template <class Key>
+      typename boost::enable_if_c<detail::make_dependent<Key>::value &&
+                                    detail::is_transparent<H>::value &&
+                                    detail::is_transparent<P>::value,
+        size_type>::type
+      count(const Key&) const;
 
       std::pair<iterator, iterator> equal_range(const key_type&);
       std::pair<const_iterator, const_iterator> equal_range(
@@ -1840,9 +1845,12 @@ namespace boost {
     }
 
     template <class K, class T, class H, class P, class A>
-    template <class TransparentKey>
-    typename unordered_map<K, T, H, P, A>::size_type
-    unordered_map<K, T, H, P, A>::count(const TransparentKey& k) const
+    template <class Key>
+    typename boost::enable_if_c<detail::make_dependent<Key>::value &&
+                                  detail::is_transparent<H>::value &&
+                                  detail::is_transparent<P>::value,
+      typename unordered_map<K, T, H, P, A>::size_type>::type
+    unordered_map<K, T, H, P, A>::count(const Key& k) const
     {
       std::size_t const key_hash =
         table::policy::apply_hash(this->hash_function(), k);