Acute injuries of the Achilles tendon are common among athletes and non-athletes alike. Injuries of other posterior calf muscles are far less common but should be considered in the differential, to ensure proper diagnosis and treatment of patients with calf injuries. This article focuses on these calf injuries, including injuries of the gastrocnemius, plantaris, soleus, and flexor hallucis longus, which may occasionally be mistaken for Achilles tendon disorders.