Back support devices for use in supporting a lower back region of an individual in a seated position are disclosed. The back support device can include a flexible, double-ended back support member adapted to provide lumbar support to the user's lower back, and a number of elastic knee straps extending from the ends of the back support member each forming a loop that can be attached to the user's knee when in a seated position. The back support device can be equipped with adjustment mechanisms for adjusting the length of the elastic knee straps and/or the length of the back support member. The back support member may further define an interior pouch that can be configured to receive a thermal pack, vibration element and/or other therapeutic device, and which can be used to store the back support device when not in use.