Fitting for a sliding door with breakout functionality, comprising an upper fitting unit , which is guided in a ceiling guide of the fitting , and a lower fitting unit , which is guided in a floor guide of the fitting , for guiding a door wing of the sliding door during normal operation along a first sliding direction and an opposite second sliding direction , wherein, in the breakout situation, the fitting units allow the door wing of the sliding door to be pivoted upwards about an axis of rotation defined by the fitting units , wherein the fitting has a locking device for the form- and/or force-fitting locking of the lower fitting unit in the floor guide against a movement in the first sliding direction and/or the second sliding direction in the breakout situation, characterized in that the locking device has a toothing extending in the floor guide along the sliding directions and a blocking element , which is rotatably mounted in the lower fitting unit and is adapted to the toothing and can be mechanically operatively connected to the door wing in such a way that pivoting of the door wing upwards in the breakout situation leads to rotation of the blocking element , as a result of which the blocking element engages in the toothing and thus the lower fitting unit is locked with a form fit in the floor guide , wherein: - the blocking element for engaging in the toothing has a blocking edge with an angle of 80° to 100°, wherein the blocking edge is adjoined by a sliding side of the blocking element , which sliding side, during normal operation, is aligned parallel to the sliding directions , or - wherein the toothing has a rack and the blocking element has a pinion matching the rack , wherein a pinion section of the pinion that faces the rack during normal operation is equipped with a toothless sliding side ; and in that the sliding side and/or a pinion hub of the pinion forms part of the guide of the door wing along the sliding directions during normal operation. in that the locking device has a toothing extending in the floor guide along the sliding directions and a blocking element , which is rotatably mounted in the lower fitting unit and is adapted to the toothing and can be mechanically operatively connected to the door wing in such a way that pivoting of the door wing upwards in the breakout situation leads to rotation of the blocking element , as a result of which the blocking element engages in the toothing and thus the lower fitting unit is locked with a form fit in the floor guide , wherein: - the blocking element for engaging in the toothing has a blocking edge with an angle of 80° to 100°, wherein the blocking edge is adjoined by a sliding side of the blocking element , which sliding side, during normal operation, is aligned parallel to the sliding directions , or - wherein the toothing has a rack and the blocking element has a pinion matching the rack , wherein a pinion section of the pinion that faces the rack during normal operation is equipped with a toothless sliding side ; - the blocking element for engaging in the toothing has a blocking edge with an angle of 80° to 100°, wherein the blocking edge is adjoined by a sliding side of the blocking element , which sliding side, during normal operation, is aligned parallel to the sliding directions , or - wherein the toothing has a rack and the blocking element has a pinion matching the rack , wherein a pinion section of the pinion that faces the rack during normal operation is equipped with a toothless sliding side ; and in that the sliding side and/or a pinion hub of the pinion forms part of the guide of the door wing along the sliding directions during normal operation. <EOS>