Abstract: A snowmobile ski lock used in combination with a ski of a snowmobile with a central track and two spread out skis, to lock the snowmobile to the ground. The lock comprises a reversed U-shaped toothed section kept in place under a ski by means of a member going around the top of the ski. The toothed section has a number of triangular teeth under its U-shaped section, which penetrate into the ground and block one ski of a snowmobile. When a thief tries to set a snowmobile into motion, the locked ski stays attached to the ground, thus causing the snowmobile to pivot around the lock and not go forward.