More people of all ages are now spending more time participating in sports, both competitive and recreational. This increase in participation has been accompanied by an increase in the number of tendon injuries. Tendons can also be injured during trauma, as part of degenerative disease and with chronic overuse. Magnetic resonance imaging (MRI) has greatly improved the ability to detect and characterize these injuries. The MRI appearance of several important tendons, in both the normal state and after injury of various types, is described and depicted in this review.