Sports and overuse injuries of the ankle and foot are commonly encountered in clinical practice. Ultrasound (US) has been established as an excellent diagnostic modality for foot and ankle injuries, providing a rapid noninvasive, economical, and readily available tool that is well tolerated by the patient with acute or chronic pain. The opportunity for dynamic examination is another advantage of US in evaluating ankle and foot pathology, where maneuvers such as muscle contraction and stressing of the joint may be particularly helpful. In many cases, US can be used as a first-line and only imaging modality for diagnosis. This article focuses on ankle disorders related to sports or overuse that affect tendons, including tendinosis, tenosynovitis, paratendinitis, rupture, dislocation, and ligaments that are commonly torn. The sonographic features of certain common foot disorders related to physical activity and overuse are also discussed, including plantar fasciitis, Morton's neuroma, stress fractures, and plantar plate injury.