diff --git a/Python/bltinmodule.c b/Python/bltinmodule.c
index 82fb9ad1651..064b8477f23 100644
--- a/Python/bltinmodule.c
+++ b/Python/bltinmodule.c
@@ -1895,7 +1895,7 @@ builtin_sum(PyObject *self, PyObject *args)
         }
         if (PyByteArray_Check(result)) {
             PyErr_SetString(PyExc_TypeError,
-                "sum() can't sum bytes [use b''.join(seq) instead]");
+                "sum() can't sum bytearray [use b''.join(seq) instead]");
             Py_DECREF(iter);
             return NULL;
         }