Powered orthosis systems and methods are disclosed. An orthosis system includes a frame, a trunk brace adapted to be secured to a user's trunk, a trunk joint coupling the trunk brace to the frame, an upper leg brace adapted to be secured to a user's upper leg, a hip joint coupling the upper leg brace to the trunk brace, a lower leg brace adapted to be secured to a user's lower leg, a knee joint coupling the lower leg brace to the upper leg brace, and a controller. The hip joint or knee joint includes an actuator operable to rotate the adjacent braces relative to each other. The controller is programmed to operate the actuator. An orthosis method includes securing a user to the orthosis system, enabling the user to walk while secured to the orthosis system, and actuating the hip or knee actuator to rotate the adjacent braces.