Traditional shoulder therapy techniques involve the physical therapist controlling and measuring forces on the patient's arm to work particular muscles. The imprecise nature of this leads to inconsistent exercises and inaccurate measurements of patient progress. Some research has shown that robotic devices can be valuable in a physical therapy setting, but most of these mechanisms do not have enough degrees of freedom in the shoulder joint to be useful in shoulder therapy, nor are they able to apply forces along the arm limbs. Based upon the shortcomings of traditional physical therapy robots and low force exoskeletons designed for virtual reality applications, requirements were generated for a robotic arm exoskeleton designed specifically for rehabilitation. Various kinematic designs were explored and compared until a final design emerged. Options for actuation were discussed, and the selection process for actuator components was detailed. Sensors were addressed in their role in the control and safety architecture. A mechanical analysis was performed on the final design to determine various properties, such as torque output, range of motion, and frequency response. Finally, a list of future work was compiled based on the final design's deficiencies.