Biomechanical analysis of the shoulder in tennis is still in early stages; however, the available data do allow some conclusions and some recommendations for conditioning, evaluation, and rehabilitation. Normal shoulder biomechanical function requires an intact kinetic chain to create the energy, produce the forces and stabilize the joint in tennis activities. Only through this mechanism can optimum performance with minimal injury risk be maintained. Conditioning of the shoulder for tennis should take this into account. Exercises should involve force generation by the large leg and trunk muscles, scapular stabilization, and closed chain co-contraction activity for the shoulder stabilizers. Similarly, clinical evaluation for shoulder problems must include assessment of areas distant to the shoulder. Kinetic chain failure can cause extra stress on the shoulder, causing or exacerbating clinical symptoms at the shoulder. Clinical evaluation of shoulder joint structures also is enhanced by knowledge of the integration of the constraint systems, and the fact that more than one system may be involved in shoulder pathology. Finally, rehabilitation efforts for shoulder problems need to focus on allowing functional return of the shoulder joint in the context of the entire kinetic chain of tennis specific activity. Rehabilitation of all areas of kinetic chain failure, such as trunk inflexibility or scapulothoracic dyskinesis, should be undertaken in conjunction with rehabilitation techniques for the shoulder. The sports medicine clinician will have a more functional framework for assessing shoulder activity and injury in tennis through the understanding of these biomechanical principles.