A restraint harness for a dog, particularly a dog of medium size and larger, including a conventional adjustable dog harness or collar and an attached control extension member. The control extension member includes a plurality of straps configured to extend to the hind end of the dog and a motion control cord that is interlaced in and between the conventional adjustable dog harness and the control extension member. The motion control cord encircles the dog's hind legs and can be tightened around the thighs with minimal force, where such tightening substantially restrains the dog without causing injury to the dog.