diff --git a/Misc/NEWS.d/next/Core_and_Builtins/2026-08-30-16-30-00.gh-issue-135385.Wn7Rd4.rst b/Misc/NEWS.d/next/Core_and_Builtins/2026-08-30-16-30-00.gh-issue-135385.Wn7Rd4.rst
new file mode 100644
index 000000000000000..43b72921fe9e45c
--- /dev/null
+++ b/Misc/NEWS.d/next/Core_and_Builtins/2026-08-30-16-30-00.gh-issue-135385.Wn7Rd4.rst
@@ -0,0 +1,3 @@
+Reduce the memory consumption of instances of classes which define
+``__slots__`` and also have a ``__dict__``.  Space for the attributes stored
+in slots is no longer reserved in the inline values of every instance.
diff --git a/Objects/dictobject.c b/Objects/dictobject.c
index 74b6d5d779a064c..cc75aa83e0b06a5 100644
--- a/Objects/dictobject.c
+++ b/Objects/dictobject.c
@@ -7286,6 +7286,11 @@ _PyDict_NewKeysForClass(PyHeapTypeObject *cls)
                 PyObject *key = PyTuple_GET_ITEM(attrs, i);
                 Py_hash_t hash;
                 if (PyUnicode_CheckExact(key) && (hash = unicode_get_hash(key)) != -1) {
+                    /* An attribute stored in a slot never uses the dict. */
+                    PyObject *descr = _PyType_Lookup((PyTypeObject *)cls, key);
+                    if (descr != NULL && Py_IS_TYPE(descr, &PyMemberDescr_Type)) {
+                        continue;
+                    }
                     if (insert_split_key(keys, key, hash) == DKIX_EMPTY) {
                         break;
                     }