diff --git a/include/pybind11/cast.h b/include/pybind11/cast.h
index db3934118..0ce9c5faa 100644
--- a/include/pybind11/cast.h
+++ b/include/pybind11/cast.h
@@ -1377,7 +1377,7 @@ inline namespace literals {
 /** \rst
     String literal version of `arg`
  \endrst */
-constexpr arg operator"" _a(const char *name, size_t) { return arg(name); }
+constexpr arg operator""_a(const char *name, size_t) { return arg(name); }
 } // namespace literals
 
 PYBIND11_NAMESPACE_BEGIN(detail)
diff --git a/include/pybind11/pytypes.h b/include/pybind11/pytypes.h
index 64aad6347..661506310 100644
--- a/include/pybind11/pytypes.h
+++ b/include/pybind11/pytypes.h
@@ -1612,7 +1612,7 @@ inline namespace literals {
 /** \rst
     String literal version of `str`
  \endrst */
-inline str operator"" _s(const char *s, size_t size) { return {s, size}; }
+inline str operator""_s(const char *s, size_t size) { return {s, size}; }
 } // namespace literals
 
 /// \addtogroup pytypes