Features for a powered prosthetic thumb are described. The thumb provides for rotation of a digit that mimics the natural movement possible with a sound thumb. The thumb may attach to a full or partial prosthetic hand or socket on a residual limb. The thumb may include an upper assembly, including a prosthetic thumb digit, rotatably attached to a mount about a pinch axis and a lateral axis. The digit may rotate about only the pinch axis, only the lateral axis, or both the pinch and lateral axes simultaneously. A first actuator may actuate to cause rotation of the digit about the pinch axis. A second actuator may actuate to cause rotation of the digit about the lateral axis. The first and second actuators may be actuated together at appropriate speeds to cause rotation about both the pinch and lateral axes simultaneously. A swaying chassis may be rotatably connected with the upper assembly and a lower assembly about various offset axes to provide for rotation about the lateral axis.