A system (10, 20, 400, 480, 590, 610, 660) for supporting an arm of a user, comprising: a harness (404, 484) configured to be worn on a torso of a user, the harness defining a vertical axis extending generally parallel to a spine of the user wearing the harness, the harness comprising a shoulder harness (404, 484) configured to be worn over or around one or both shoulders of the user, and a torso bracket (416, 486, 612, 614) comprising a first end coupled to the shoulder harness and a second end configured to terminate adjacent the user's shoulder adjacent the arm being supported; an arm support coupled to the harness and including an arm rest (120, 508, 674) configured to support a portion of an arm of the user, the arm support comprising a shoulder bracket (106, 206, 618) pivotally coupled to the second end of the torso bracket such that the shoulder bracket is rotatable about a vertical pivot point (107, 207) generally parallel to the vertical axis and an arm bracket (108, 208, 624) pivotally coupled to the shoulder bracket such that the arm bracket is rotatable about a horizontal pivot point generally orthogonal to the vertical axis without substantially interfering with movement of the user's arm while the user's arm is supported by the arm rest, the arm bracket carrying the arm rest; and the system characterized by further comprising one or more compensation elements (112, 212, 500, 680) comprising a spring coupled to the shoulder bracket and arm bracket to apply a torsional load to the arm bracket about the horizontal pivot point to at least partially offset a gravitational force acting on the arm of the user as the user moves and the arm support follows the user's movement. a harness (404, 484) configured to be worn on a torso of a user, the harness defining a vertical axis extending generally parallel to a spine of the user wearing the harness, the harness comprising a shoulder harness (404, 484) configured to be worn over or around one or both shoulders of the user, and a torso bracket (416, 486, 612, 614) comprising a first end coupled to the shoulder harness and a second end configured to terminate adjacent the user's shoulder adjacent the arm being supported; an arm support coupled to the harness and including an arm rest (120, 508, 674) configured to support a portion of an arm of the user, the arm support comprising a shoulder bracket (106, 206, 618) pivotally coupled to the second end of the torso bracket such that the shoulder bracket is rotatable about a vertical pivot point (107, 207) generally parallel to the vertical axis and an arm bracket (108, 208, 624) pivotally coupled to the shoulder bracket such that the arm bracket is rotatable about a horizontal pivot point generally orthogonal to the vertical axis without substantially interfering with movement of the user's arm while the user's arm is supported by the arm rest, the arm bracket carrying the arm rest; and the system characterized by further comprising one or more compensation elements (112, 212, 500, 680) comprising a spring coupled to the shoulder bracket and arm bracket to apply a torsional load to the arm bracket about the horizontal pivot point to at least partially offset a gravitational force acting on the arm of the user as the user moves and the arm support follows the user's movement.