The pectineus muscle is a small muscle locates in the mid-thigh of the leg. Its physiologic role is in the flexing and adducting (drawing inward toward the body) of the thigh. Due to its location and function, it is classified as a pelvic muscle. It is supplied with oxygen and nutrients by the femoral and deep femoral arteries of the leg and pelvis.

The pectineus muscle is located close to other muscles of the pelvis and thigh, such as the adductor longus, and forms part of the femoral triangle. It runs from the pelvis and along the femur in the upper leg. However, this muscle is relatively small in comparison to other muscles of the thigh. This muscle is unusual in that its exact anatomical location can differ slightly from person to person. It lies on the boundary of two compartments (functional groups) of muscles in the leg. The pectineus muscle can be placed in the anterior (front) or the medial compartment, and can also be innervated by two different nerves.