A vehicle having a sliding door arranged behind a body pillar, a frame around the door opening closeable by the sliding door, a rail system provided in the region of the sliding door connected fixedly to the vehicle and having upper and lower guide rails, sliding carriages provided on the sliding door connected to the sliding door via a respective supporting arm and guided displaceably on the guide rails, and side impact protection in the region of the sliding door. At least one of the sliding carriages or supporting arms is provided with a stop. In the event of a side impact, in which the outer vehicle wall is deformed in the direction of the vehicle interior, an abutment connected to the vehicle wall comes to bear against the stop of the sliding carriage or of the supporting arm, and the position of the sliding door is thereby blocked.