A motion picture projector wherein the top wall of the housing is provided with an inwardly extending chamber for reception of smaller or larger magazines for motion picture film or for reception of smaller or larger exposed supply reels for motion picture film. The housing contains an automatic threading unit for the leader of motion picture film in a magazine and a manually operated threading unit serving for threading of motion picture film which is stored on an exposed supply reel. The reel can be mounted for rotation in the chamber by moving a mandrel from a retracted position to an extended position in which the mandrel extends through the central opening in the core of the reel. Such movement of the mandrel is utilized to move an obstructing member away from the inlet for manual threading of motion picture film which is stored on a reel.