Abstract: A modular lock assembly for placement in an opening in a frame of a cabinet locker that is located adjacent to a door of the cabinet locker. The modular lock assembly includes a mounting plate for removeably being positioned in the opening. A locking plate is moveably connected to the mounting plate. An electromechanical actuator is connected to the mounting plate and coupled with the locking plate to automatically provide the movement of the locking plate. An input device is electrically connected to the electromechanical actuator for activating the electromechanical actuator in response to inputs. The mounting plate defines a custodian opening for receiving a custodian lock for locking the mounting plate to the frame. At least one tongue extends from the mounting plate in spaced relationship with the custodian opening for engaging the frame for further securing the mounting plate to the frame.