Sartorius is a long thin muscle that runs down the length of the thigh.

It attaches superiorly to the anterior superior iliac spine of the hip bone, and crosses over the front of the thigh, to insert at the medial side of the upper tibia.

The name sartorius comes from the Latin word sartus meaning 'patched or repaired'. This refers the cross-legged position in which tailors once sat. The action of sartorius is to cross the legs, by flexion of the knee, and flexion and lateral rotation the hip. Sartorius does not have a very strong action.

Situated in the anterior fascial compartment of the thigh, sartorius is innervated via branches of the femoral nerve. Sartorius forms the lateral side of the femoral triangle.

Sartorius is also the surname of a family of Polish nobility also established in Spain.