Abstract: An orthosis (10) for supination-pronation of the human wrist (92) generally comprises arm cuff (20) secured to arm (80) including forearm platform (26) on forearm (87) directly adjacent elbow (84), a wrist connector (30) including swing arm (33) having a wrist end (36) and an upper end (34) pivotally connected to forearm platform (26) near elbow (84) and about a pivot axis radial to the longitudinal axis of forearm (87), and a wrist cuff (50) adapted to be secured adjacent wrist (92) including a wrist pivot (56) connected to wrist end (36) of swing arm (33). A swinging mechanism (70) applies a force between arm cuff (20) and wrist connector (30) for pivoting swing arm (33) and thereby rotating wrist (92). The length of swing arm (33) is selectably adjustable. Wrist end (36) can be rotated about the longitudinal axis of swing arm (33). Swing arm (33) is attached to wrist connector (55) at selected radial distances from the wrist pivot axis and at selected radial distances from wrist cuff (50).