Injury and degeneration of tendon, the soft tissue that mechanically links muscle and bone, can cause substantial pain and loss of function. This review discusses the composition and function of healthy tendon and describes the structural, biological, and mechanical changes initiated during the process of tendon healing. Biochemical pathways activated during repair, experimental injury models, and parallels between tendon healing and tendon development are emphasized, and cutting-edge strategies for the enhancement of tendon healing are discussed.