The extensor tendon system of the hand is anatomically complex and prone to injury due to its superficial location and close proximity to underlying bony structures. While such injuries often occur in conjunction with fractures, they are rarely accompanied by neurovascular damage. This chapter provides an overview of the anatomical features of the extensor mechanism, common injury patterns, surgical repair techniques, and postoperative rehabilitation strategies.The extensor mechanism comprises extrinsic and intrinsic muscle groups, along with fibrous connective structures. Tendons within this system vary in thickness and shape along their course, being broader and thicker proximally and thinner distally, which presents challenges for surgical repair. Selection of repair technique depends on the injury zone and aims to minimize tendon shortening while maximizing tensile strength. Epitendinous suturing is particularly beneficial in mid-level zones (2–4), while core and epitendinous suture combinations are preferred for proximal injuries (zone 6 and above).Stronger repairs are achieved with multi-strand core sutures, typically using at least four strands, complemented by epitendinous sutures which enhance strength and reduce adhesion formation. Postoperative protocols must balance tendon healing with early mobilization to optimize functional outcomes. Dynamic rehabilitation approaches have shown superiority over static protocols in many cases; however, certain injuries, such as mallet finger, may still require prolonged immobilization with static splinting.