Abstract: A tractor ball assembly to be mounted on the tongue at the rear end of the tractor having a plurality of balls to match the variously-sized sockets commonly used. The ball is mounted on a base which rests on the tractor tongue. Frusto-conical sections of identifical size and shape diamatrically opposed are cut in each ball and the upper side of the base has a surface complementary to the surface of one of the frusto-conical sections. A bolt, the under side of the head of which is a surface complementary to the ball frusto-conical surfaces fits into aligned holes in the ball, base and tongue and upon being tightened keeps the ball from slipping with respect to the base and/or the bolt.