diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index 4093b69be6..76e5743539 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -400,6 +400,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         'istartswith': "LIKE UPPER(%s) ESCAPE '\\'",
         'iendswith': "LIKE UPPER(%s) ESCAPE '\\'",
     }
+    oracle_version = None
 
     def _valid_connection(self):
         return self.connection is not None
@@ -414,6 +415,10 @@ class DatabaseWrapper(BaseDatabaseWrapper):
             else:
                 conn_string = "%s/%s@%s" % (settings.DATABASE_USER, settings.DATABASE_PASSWORD, settings.DATABASE_NAME)
                 self.connection = Database.connect(conn_string, **self.options)
+            try:
+                self.oracle_version = int(self.connection.version.split('.')[0])
+            except ValueError:
+                pass
         cursor = FormatStylePlaceholderCursor(self.connection)
         # Default arraysize of 1 is highly sub-optimal.
         cursor.arraysize = 100
diff --git a/django/db/models/query.py b/django/db/models/query.py
index a750ef5550..23d0bac6c8 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -816,6 +816,9 @@ def get_where_clause(lookup_type, table_prefix, field_name, value, db_type):
         return connection.ops.fulltext_search_sql(field_sql)
     elif lookup_type in ('regex', 'iregex'):
         if settings.DATABASE_ENGINE == 'oracle':
+            if connection.oracle_version and connection.oracle_version <= 9:
+                msg = "Regexes are not supported in Oracle before version 10g."
+                raise NotImplementedError(msg)
             if lookup_type == 'regex':
                 match_option = 'c'
             else: