diff --git a/panda/src/express/ordered_vector.I b/panda/src/express/ordered_vector.I
index a8ba4fd93e..027306ade4 100644
--- a/panda/src/express/ordered_vector.I
+++ b/panda/src/express/ordered_vector.I
@@ -633,6 +633,17 @@ push_back(const value_type &key) {
   _vector.push_back(key);
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: ordered_vector::pop_back
+//       Access: Public
+//  Description: Removes the last element at the end of the vector.
+////////////////////////////////////////////////////////////////////
+template<class Key, class Compare>
+INLINE void ordered_vector<Key, Compare>::
+pop_back() {
+  _vector.pop_back();
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: ordered_vector::nci
 //       Access: Private
diff --git a/panda/src/express/ordered_vector.h b/panda/src/express/ordered_vector.h
index c04d1261a4..03b075b775 100644
--- a/panda/src/express/ordered_vector.h
+++ b/panda/src/express/ordered_vector.h
@@ -201,6 +201,7 @@ public:
   bool verify_list_nonunique() const;
 
   INLINE void push_back(const VALUE_TYPE &key);
+  INLINE void pop_back();
 
 private:
   INLINE ITERATOR nci(CONST_ITERATOR i);