A slide rail assembly includes a sliding rail and a supporting device. The supporting device includes a supporting bracket and a sliding bracket. The supporting bracket defines at least one sliding slot along an extending direction of the supporting bracket, and the sliding bracket defines at least one sliding portion corresponding to the at least one sliding slot. The sliding bracket is slidably connected to the supporting bracket through the at least one sliding portion and the at least one sliding slot, the sliding bracket is mounted to the sliding rail. The supporting device is also disclosed.