diff --git a/django/db/backends/mysql/schema.py b/django/db/backends/mysql/schema.py
index 08e883d80c..dc74b2db2a 100644
--- a/django/db/backends/mysql/schema.py
+++ b/django/db/backends/mysql/schema.py
@@ -6,7 +6,7 @@ class DatabaseSchemaEditor(BaseDatabaseSchemaEditor):
     sql_rename_table = "RENAME TABLE %(old_table)s TO %(new_table)s"
 
     sql_alter_column_null = "MODIFY %(column)s %(type)s NULL"
-    sql_alter_column_not_null = "MODIFY %(column)s %(type)s NULL"
+    sql_alter_column_not_null = "MODIFY %(column)s %(type)s NOT NULL"
     sql_alter_column_type = "MODIFY %(column)s %(type)s"
     sql_rename_column = "ALTER TABLE %(table)s CHANGE %(old_column)s %(new_column)s %(type)s"