diff --git a/Lib/mzscheme/std_string.i b/Lib/mzscheme/std_string.i
index 7885e7ef8..0781b5867 100644
--- a/Lib/mzscheme/std_string.i
+++ b/Lib/mzscheme/std_string.i
@@ -20,6 +20,8 @@
 
 namespace std {
 
+    %naturalvar string;
+
     class string;
 
     /* Overloading check */
diff --git a/Lib/ocaml/std_string.i b/Lib/ocaml/std_string.i
index 046766984..c43664aa3 100644
--- a/Lib/ocaml/std_string.i
+++ b/Lib/ocaml/std_string.i
@@ -24,6 +24,8 @@
 
 %include <std_vector.i>
 
+%naturalvar std::string;
+
 namespace std {
     template <class charT> class basic_string {
     public:
diff --git a/Lib/pike/std_string.i b/Lib/pike/std_string.i
index b8d994509..07c3fe60c 100644
--- a/Lib/pike/std_string.i
+++ b/Lib/pike/std_string.i
@@ -11,6 +11,8 @@
 
 namespace std {
 
+    %naturalvar string;
+
     class string;
 
     /* Overloading check */