A pair of accessory quadriceps femoris muscles was found in only one male out of 200 Nigerian cadavers examined. Thus, this unusual muscle was of rare occurrence in Nigerians. Morphologically, the accessory muscle seemed to be a part of the vastus lateralis muscle bilaminated. It arose from the femur and inserted into the patella via the common quadriceps femoris tendon, supplied by the profunda femoris artery, drained into the profunda femoris vein, and was innervated by the femoral nerve. It was suggested that such an accessory quadriceps femoris was worthy of note for anatomists as well as for orthopedic surgeons.