A jumping knee strike used in Muay Thai.

An Knee Strike is a strike made with the area of the leg around the knee (some styles strike with the kneecap, however, this can be dangerous). They can be devastating in close-range combat, especially in a clinch, and for this reason are banned from many competitions (some, however, still allow their use, such as Muay Thai and Ultimate Fighting Championship).

Knees can be used forwards (called a straight knee) or from an angle (called a roundhouse knee). Other variants include the downward knee and crescent knee strikes. They can be applied while standing, especially in a clinch, on the ground (in some situations), or while jumping (this is commonly seen in Muay Thai). Targets include the thigh, groin, ribs, solar plexus, and head.

Due to their effectiveness, they are very common in traditional martial arts such as hapkido, taekwondo, karate, and Silat, among others.