A self-closing slide rail assembly includes a first rail, a second rail, and a self-closing mechanism. The second rail is longitudinally displaceable relative to the first rail. The self-closing mechanism includes a housing, an elastic member, and a movable member. The housing is mounted on the first rail. The movable member is movable within the housing in response to the elastic energy released by the elastic member. The second rail is retracted relative to the first rail by the movable member upon engagement therewith when moving from an extended position toward a retracted position.