Abstract: An adjustable joint for a knee orthosis or brace. The joint preferably has a polycentric pivot with first and second members having mating, gear teeth and outwardly extending, elongated bars. As one member rotates about its axis, it causes the other member to rotate in an opposite direction about its axis with the bars travelling along respective first and second paths. In the disclosed embodiments, stop members are selectively positioned along the travel paths of the bars with a portion of one in the path of the upper bar which is attached to the thigh engaging component of the brace and a portion of the other in the path of the lower bar attached to the calf engaging component of the brace. The portions of each stop member are preferably eccentrically mounted for rotation about axes spaced from and parallel to the axes of the first and second members of the polycentric pivot.