Abstract: A lock for a sliding door (14), with a lock case (24) for receiving a lock cylinder (30), the lock cylinder (30) being arranged in a recess (36) of the lock case (24) such that, in order to lock the lock (22), a bolt (28) of the lock case (24) is brought into engagement with a striking plate (26) of the lock (22) by a rotationally actuable driver (32) of the lock cylinder (30). The lock (22) has at least one support part (38, 40) which is arranged laterally on the lock case (24) in the region of the recess (36) to support the lock cylinder (30). A further characteristic relates to the securing of the lock against removal and for this purpose, the or each support part (38, 40) is fastened to the lock case (24) by retaining pins (60), a lock cylinder screw (58) for fastening the lock cylinder (30) to the lock case (24) being in engagement with the or each retaining pin (60) to prevent removal of the support parts (38, 40) and of the retaining pins (60).