diff --git a/src/arrays.sip b/src/arrays.sip
index 5b521c38..207d5560 100644
--- a/src/arrays.sip
+++ b/src/arrays.sip
@@ -59,7 +59,7 @@
             }
             PyErr_Clear();
             wxString string;
-            size_t len = PyUnicode_GET_LENGTH(item);
+            size_t len = PyUnicode_AsWideChar(item, NULL, 0);
             if (len) {
                 wxPyUnicode_AsWideChar(item, wxStringBuffer(string, len), len);
             }
diff --git a/src/string.sip b/src/string.sip
index 2f39bb29..c7d09e33 100644
--- a/src/string.sip
+++ b/src/string.sip
@@ -45,7 +45,7 @@
             }
         }
         *sipCppPtr = new wxString();
-        size_t len = PyUnicode_GET_LENGTH(uni);
+        size_t len = PyUnicode_AsWideChar(uni, NULL, 0);
         if (len) {
             wxPyUnicode_AsWideChar(uni, wxStringBuffer(**sipCppPtr, len), len);
         }
diff --git a/src/wxpy_api.sip b/src/wxpy_api.sip
index 765dfa8a..16457415 100644
--- a/src/wxpy_api.sip
+++ b/src/wxpy_api.sip
@@ -54,7 +54,7 @@ static wxString i_Py2wxString(PyObject* source)
         }
     }
     wxString target;
-    size_t len = PyUnicode_GET_LENGTH(uni);
+    size_t len = PyUnicode_AsWideChar(uni, NULL, 0);
     if (len) {
         wxPyUnicode_AsWideChar(uni, wxStringBuffer(target, len), len);
     }
@@ -84,7 +84,7 @@ static wxString i_Py2wxString(PyObject* source)
 //        }
 //    }
 //    // TODO: Coerce non-unicode types to unicode here?  (Classic does)
-//    size_t len = PyUnicode_GET_LENGTH(uni);
+//    size_t len = PyUnicode_AsWideChar(uni, NULL, 0);
 //    if (len) {
 //        wxPyUnicode_AsWideChar(uni, wxStringBuffer(str, len), len);
 //    }