Reconstruction of the proximal humerus after tumour resection is a surgical challenge. The goal consists not only in reconstructing the resected bone segment, but also in restoring a stable and mobile shoulder. The choice of the technique depends on the status of the soft-tissues at the end of the resection. The preoperative work-up must determine the oncological goals of the resection and identify the structures that can be spared. When deltoid muscle function is preserved, a reverse prosthesis offers the best stability and mobility outcomes. The objective of this work is to describe the indications and techniques used in the various available reconstruction methods. Shoulder mobilities are restored using some of these methods and lost with others. Emphasis is put on the reverse shoulder prosthesis, with a description of its variants (standard prosthesis, cement sleeve, allograft-prosthesis composite, and massive prosthesis) and a discussion of the management of its early complications. When performing reverse shoulder arthroplasty, glenoid implant preparation and positioning are crucial to achieve stability, and humeral length restoration will govern soft-tissue tension. Latissimus dorsi tendon transfer is required to restore active external rotation if the posterior rotator cuff tendons have been removed. Allograft-anatomic prosthesis composites, osteo-cartilaginous allografts, arthrodesis, and spacer prostheses are proposed for patients in whom the local conditions preclude implantation of a reverse shoulder prosthesis.