A modular lock (1) for a door (2) of a motor vehicle is provided with a closure module (16) and a control module (17). The closure module (16) is provided with a first support body (18) which is integral with the door (2), and a closure mechanism (19) which is supported by the first support body (18) and can be connected to a striker (3) which is integral with an upright of the door (2), in order to give rise to closure of the door (2) itself. The control module (17) is provided with a second support body (20) which is integral with the door (2), and with an actuating assembly (21) which is supported by the second support body (20), and can control release of the closure mechanism (19) from the striker (3). The lock (1) is also provided with a flexible transmission (23) for remote connection between the actuating assembly (21) and the closure mechanism (19), in order to permit remote positioning of the closure module (16) and the control module (17) on the door (2).