diff --git a/Lib/test/test_import.py b/Lib/test/test_import.py
--- a/Lib/test/test_import.py
+++ b/Lib/test/test_import.py
@@ -410,16 +410,25 @@ class ImportTests(unittest.TestCase):
                               "sys.modules['sa'] = sys.modules[__name__];"
                               "import sa")
             sys.path.insert(0, dir_name)
             # a segfault means the test failed!
             import sa
         finally:
             rmtree(dir_name)
 
+    def test_fromlist_error_messages(self):
+        # Test for issue #21720: fromlist unicode error messages
+        with self.assertRaises(TypeError) as cm:
+            __import__('encodings', fromlist=[u'aliases'])
+        self.assertIn("must be str, not unicode", str(cm.exception))
+        with self.assertRaises(TypeError) as cm:
+            __import__('encodings', fromlist=[1])
+        self.assertIn("must be str, not int", str(cm.exception))
+
 
 class PycRewritingTests(unittest.TestCase):
     # Test that the `co_filename` attribute on code objects always points
     # to the right file, even when various things happen (e.g. both the .py
     # and the .pyc file are renamed).
 
     module_name = "unlikely_module_name"
     module_source = """
diff --git a/Python/import.c b/Python/import.c
--- a/Python/import.c
+++ b/Python/import.c
@@ -2586,18 +2586,19 @@ ensure_fromlist(PyObject *mod, PyObject 
         if (item == NULL) {
             if (PyErr_ExceptionMatches(PyExc_IndexError)) {
                 PyErr_Clear();
                 return 1;
             }
             return 0;
         }
         if (!PyString_Check(item)) {
-            PyErr_SetString(PyExc_TypeError,
-                            "Item in ``from list'' not a string");
+            PyErr_Format(PyExc_TypeError,
+                         "Item in ``from list'' must be str, not %200s",
+                         Py_TYPE(item)->tp_name);
             Py_DECREF(item);
             return 0;
         }
         if (PyString_AS_STRING(item)[0] == '*') {
             PyObject *all;
             Py_DECREF(item);
             /* See if the package defines __all__ */
             if (recursive)