A sliding door lock system comprising a sliding door lock mechanism having a top plate which is fixed to a door frame via two flaps, each comprising a bolt receiving element for fixing the sliding door lock mechanism to the door frame using a fixing element, said top plate being shifted with respect to the door frame so that a cavity is formed, limited by side walls extending between the shifted part of the top plate and the flaps, said sliding door lock system comprising a reinforcement element which is disposed on at least one of the flaps and next to at least one of the side walls, wherein a support wall of the reinforcement element is adapted to support the adjacent side wall of the sliding door lock mechanism so that an outward deformation or a bending can be prevented.