An adjustable knee brace for fitting a variety of leg sizes and adjustable to limit flexion or extension motion of a knee. The knee brace includes an adjustable length provided by a strut that telescopes within a receiver. A latch assembly mounted on the receiver selectively applies a frictional force to lock the strut member and the receiver against relative telescoping movement. An adjustable range of motion hinge is operatively associated with the telescoping strut. The hinge includes a hinge plate connected to the strut member and having a semi-circular peripheral edge defining a plurality of uniformly spaced apart keys. A range of motion stop is movably positionable relative to the semi-circular peripheral edge and includes a movable latch having teeth. The latch is movable away from the keys to an unlocked position in which the stop is movable relative to the keys, and the movable latch is movable toward and into engagement with the keys to a locked position in which the range of motion stop is not movable relative to the keys. The range of motion stop defines a limit of rotational movement of the range of motion hinge to limit extension or flexion motion of the knee.