A slide rail assembly, comprising: a first rail; a second rail displaceable between a retracted position and an extended position with respect to the first rail; a stop and a locking device, the stop being connected to the first rail; wherein the locking device comprises a first engaging member and a first releasing member; wherein the first engaging member is pivotally connected to the second rail, and when the second rail is at the retracted position with respect to the first rail, the first engaging member is at an engaged position with respect to the stop; and wherein the first releasing member is configured to operatively drive the first engaging member away from the engaged position, thereby allowing the second rail to be displaced from the retracted position toward the extended position with respect to the first rail, and wherein the locking device further comprises an elastic member for applying an elastic force to the first engaging member characterized in that the slide rail assembly further comprises a bracket, and the locking device further includes a second releasing member connected to the second rail and a second engaging member, and in that the slide rail assembly is configured to be mounted to a rack, and the bracket is connected to the first rail and has an opening and is connectable to the rack, and the second engaging member is movably mounted on the bracket, has an engaging projection jutting out of the opening of the bracket, and is configured to be driven by the second releasing member so that the engaging projection of the second engaging member is displaced and drives a driven member which is movably mounted on the rack into displacement, and in that the stop is connected to the first rail via the bracket; and in that once the second rail is displaced from the extended position toward the retracted position with respect to the first rail and reaches a predetermined positon, the elastic member is pressed against the stop of the bracket such that the first engaging member returns to the engaged position due to the elastic force of the elastic member and thus displaces the first releasing member with respect to the second releasing member. a first rail; a second rail displaceable between a retracted position and an extended position with respect to the first rail; a stop and a locking device, the stop being connected to the first rail; wherein the locking device comprises a first engaging member and a first releasing member; wherein the first engaging member is pivotally connected to the second rail, and when the second rail is at the retracted position with respect to the first rail, the first engaging member is at an engaged position with respect to the stop; and wherein the first releasing member is configured to operatively drive the first engaging member away from the engaged position, thereby allowing the second rail to be displaced from the retracted position toward the extended position with respect to the first rail, and wherein the locking device further comprises an elastic member for applying an elastic force to the first engaging member characterized in that the slide rail assembly further comprises a bracket, and the locking device further includes a second releasing member connected to the second rail and a second engaging member, and in that the slide rail assembly is configured to be mounted to a rack, and the bracket is connected to the first rail and has an opening and is connectable to the rack, and the second engaging member is movably mounted on the bracket, has an engaging projection jutting out of the opening of the bracket, and is configured to be driven by the second releasing member so that the engaging projection of the second engaging member is displaced and drives a driven member which is movably mounted on the rack into displacement, and in that the stop is connected to the first rail via the bracket; and in that once the second rail is displaced from the extended position toward the retracted position with respect to the first rail and reaches a predetermined positon, the elastic member is pressed against the stop of the bracket such that the first engaging member returns to the engaged position due to the elastic force of the elastic member and thus displaces the first releasing member with respect to the second releasing member.