A locking system for co-mounted doors, wherein a first door and a second door are to be hinged along a common side to a door frame so that a first lock assembly when mounted to the first door can move proximate to and engage with a second lock assembly when mounted in alignment with the first lock assembly to the second door, the locking system comprising the first lock assembly, the first lock assembly including a first rotatable component that can be caused to rotate by a user, and the second lock assembly, the second lock assembly including a second rotatable component that can be caused to rotate by the user, wherein at least one of the first and second lock assemblies include a lockbolt or latch in operable connection with at least one of the first and second rotatable components for locking and unlocking at least one of the first and second doors to the door frame when installed, and further wherein the first lock assembly comprises a first alignment component operatively rotationally connected with the first rotatable component and the second lock assembly comprises a second alignment component operatively rotationally connected with the second rotatable component that will engage with one another upon moving the first door proximate to the second door, at least one of the first and second alignment components having a predetermined rotational orientation for engagement with the other of the first and second alignment components, the first and second alignment components each including interacting surfaces that during engagement with one another rotationally align the first and second alignment components with one another to create an effective rotational translational connection from the first lock assembly to the second lock assembly, whereby user initiated rotation of either the first or second rotatable component can cause locking or unlocking of the lockbolt or latch in one of or both the first and second doors.