A slide rail assembly, comprising: a first rail including a first wall, a second wall, and a longitudinal wall connected between the first wall and the second wall; a second rail displaceable with respect to the first rail; and a first bracket device disposed adjacent to the first rail and including a bracket, wherein the bracket includes an upper wall, a lower wall, a sidewall, a first extension section, and a second extension section, the sidewall is connected between the upper wall and the lower wall, the first extension section extends from and is bent with respect to the upper wall, and the second extension section extends from and is bent with respect to the lower wall; wherein the upper wall, the lower wall, and the sidewall of the bracket correspond in position to the first wall, the second wall, and the longitudinal wall of the first rail respectively, and the first extension section and the second extension section of the bracket are configured to produce a retaining effect on a lateral side of the first wall of the first rail and a lateral side of the second wall of the first rail respectively; wherein the slide rail assembly further comprises: a third rail movably mounted between the first rail and the second rail, and a reinforcing base connected to a backside of the first rail, wherein the reinforcing base includes a mounting channel, the bracket further includes an extension support member connected to the sidewall and is mounted in the mounting channel of the reinforcing base via the extension support member, the extension support member and the reinforcing base have a first position-limiting feature and a second position-limiting feature respectively, and the first position-limiting feature and the second position-limiting feature correspond in position to each other; wherein when the second rail is at an extended position with respect to the first rail, a rear end portion of the second rail is a predetermined distance ahead of a front end portion of the first rail; and wherein the first bracket device is disposed adjacent to the front end portion of the first rail. a first rail including a first wall, a second wall, and a longitudinal wall connected between the first wall and the second wall; a second rail displaceable with respect to the first rail; and a first bracket device disposed adjacent to the first rail and including a bracket, wherein the bracket includes an upper wall, a lower wall, a sidewall, a first extension section, and a second extension section, the sidewall is connected between the upper wall and the lower wall, the first extension section extends from and is bent with respect to the upper wall, and the second extension section extends from and is bent with respect to the lower wall; wherein the upper wall, the lower wall, and the sidewall of the bracket correspond in position to the first wall, the second wall, and the longitudinal wall of the first rail respectively, and the first extension section and the second extension section of the bracket are configured to produce a retaining effect on a lateral side of the first wall of the first rail and a lateral side of the second wall of the first rail respectively; wherein the slide rail assembly further comprises: a third rail movably mounted between the first rail and the second rail, and a reinforcing base connected to a backside of the first rail, wherein the reinforcing base includes a mounting channel, the bracket further includes an extension support member connected to the sidewall and is mounted in the mounting channel of the reinforcing base via the extension support member, the extension support member and the reinforcing base have a first position-limiting feature and a second position-limiting feature respectively, and the first position-limiting feature and the second position-limiting feature correspond in position to each other; wherein when the second rail is at an extended position with respect to the first rail, a rear end portion of the second rail is a predetermined distance ahead of a front end portion of the first rail; and wherein the first bracket device is disposed adjacent to the front end portion of the first rail.