An apparatus for preventing the car door section of an elevator car from being opened when the elevator car is not located at an authorized landing zone in the elevator shaft. A car door locking device includes a locking mechanism connected to and movable with the car door section. The locking mechanism has a first member, a second member, and apparatus for connecting the second member for limited guided movement with respect to the first member between a locked position and an unlocked position. A spring is provided for normally urging the second member toward the locked position with respect to the first member. A first stop is attached to and movable with the second member. A second stop, fixed in position with respect to the car door section, is provided for selectively engaging the movable stop. Apparatus is provided for moving the second member to the unlocked position only when the elevator car is located in an authorized landing zone in the elevator shaft, whereby the movable stop engages the fixed stop to prevent the car door section from being opened only when the second member is in the locked position and the movable stop does not engage the fixed stop when the second member is in the unlocked position.