diff --git a/include/boost/static_string/config.hpp b/include/boost/static_string/config.hpp
index 5af2b13..35dcdec 100644
--- a/include/boost/static_string/config.hpp
+++ b/include/boost/static_string/config.hpp
@@ -279,4 +279,11 @@ using basic_string_view =
 #define BOOST_STATIC_STRING_USE_STD_FORMAT
 #endif
 
+#if defined(__GNUC__) && (__GNUC__ >= 5) && (__GNUC__ <= 10) && !defined(__clang__)
+// Workaround for GCC complaining about nested classes being private.
+#define BOOST_STATIC_STRING_GCC_NESTED_CLASS_WORKAROUND public:
+#else
+#define BOOST_STATIC_STRING_GCC_NESTED_CLASS_WORKAROUND
+#endif
+
 #endif
diff --git a/include/boost/static_string/static_string.hpp b/include/boost/static_string/static_string.hpp
index b350a98..75556d3 100644
--- a/include/boost/static_string/static_string.hpp
+++ b/include/boost/static_string/static_string.hpp
@@ -322,6 +322,8 @@ class static_string_base
   using pointer = value_type*;
   using const_pointer = const value_type*;
 
+BOOST_STATIC_STRING_GCC_NESTED_CLASS_WORKAROUND
+
   struct size
   {
     class basic_static_string
@@ -388,6 +390,8 @@ class static_string_base<0, CharT, Traits>
   using value_type = typename Traits::char_type;
   using pointer = value_type*;
 
+BOOST_STATIC_STRING_GCC_NESTED_CLASS_WORKAROUND
+
   struct size
   {
     class basic_static_string