diff --git a/include/gsl/string_span b/include/gsl/string_span
index 85112e5..37cbe15 100644
--- a/include/gsl/string_span
+++ b/include/gsl/string_span
@@ -20,7 +20,6 @@
 #include <gsl/gsl_assert> // for Ensures, Expects
 #include <gsl/gsl_util>   // for narrow_cast
 #include <gsl/span>       // for operator!=, operator==, dynamic_extent
-#include <gsl/pointers>   // for not_null
 
 #include <algorithm> // for equal, lexicographical_compare
 #include <array>     // for array