diff --git a/Include/dictobject.h b/Include/dictobject.h
index 36053e8..d3a0fc5 100644
--- a/Include/dictobject.h
+++ b/Include/dictobject.h
@@ -116,9 +116,9 @@
 					   PyObject *seq2,
 					   int override);
 
-PyAPI_FUNC(PyObject *) PyDict_GetItemString(PyObject *dp, char *key);
-PyAPI_FUNC(int) PyDict_SetItemString(PyObject *dp, char *key, PyObject *item);
-PyAPI_FUNC(int) PyDict_DelItemString(PyObject *dp, char *key);
+PyAPI_FUNC(PyObject *) PyDict_GetItemString(PyObject *dp, const char *key);
+PyAPI_FUNC(int) PyDict_SetItemString(PyObject *dp, const char *key, PyObject *item);
+PyAPI_FUNC(int) PyDict_DelItemString(PyObject *dp, const char *key);
 
 #ifdef __cplusplus
 }
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 712ec2c..5e39dfa 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -1919,7 +1919,7 @@
 /* For backward compatibility with old dictionary interface */
 
 PyObject *
-PyDict_GetItemString(PyObject *v, char *key)
+PyDict_GetItemString(PyObject *v, const char *key)
 {
 	PyObject *kv, *rv;
 	kv = PyString_FromString(key);
@@ -1931,7 +1931,7 @@
 }
 
 int
-PyDict_SetItemString(PyObject *v, char *key, PyObject *item)
+PyDict_SetItemString(PyObject *v, const char *key, PyObject *item)
 {
 	PyObject *kv;
 	int err;
@@ -1945,7 +1945,7 @@
 }
 
 int
-PyDict_DelItemString(PyObject *v, char *key)
+PyDict_DelItemString(PyObject *v, const char *key)
 {
 	PyObject *kv;
 	int err;