Abstract: An osteotomy guide having a frame and a pair of guide pins, for creating a desired cut in a bone. The frame has an outer frame, and an inner frame which is telescopically mounted within the outer frame. Both the inner frame and outer frame having open ends and a guide pin sleeve. The inner frame and outer frame together define a main slot which is adjustable in length by moving the inner frame with respect to the outer frame. The frame is mounted to the bone by creating anchoring holes in the bone and extending the guide pins through the guide pin sleeves and into the anchoring holes, such that the guide pins are parallel in all planes. A controlled cut is created by using the guide pins as a visual guide or inserting a saw blade through the main slot.