High School Jingi

Both series are about perverted hooligan-type protagonists who have ulterior motives for becoming teachers. They use violence to deal with delinquent misfits in their class and elsewhere on campus, with Jouji being more vicious in this regard than Onizuka. Their main love interests are both naive female colleagues who (at least for the one and only OVA episode of High School Jingi) are ineffectual and unable to stop the protagonists' misbehaviour. If you are a fan of GTO's crass, over-the-top comedic scenes then you will probably enjoy High School Jingi since it is a pure comedy with none of the (melo)drama present in GTO.