A portable overhead projector having a folding arm. The arm and a torque member are pivotally attached to the projector head, forming a four bar linkage. When the arm is moved from an upright, operative position to a storage position, the projector head rotates so as to be flush with the base of the projector, making the projector more compact for storage. An adjustment mechanism is also provided to automatically open and close a mirror which is attached to the projector head, simplifying the set up procedure of the overhead projector.