Abstract: A task chair is disclosed, including a base, a seat supported by the base, and a pair of uprights connected to the base and extending upwardly from the seat. A pair of armrests are attached respectively to the uprights, and are selectively positionable along the uprights in a manner in which the height of the armrests along the uprights is adjustable. A backrest is also selectively positionable along the uprights, and the height of the backrest with respect to the seat may be adjusted by moving the backrest upwardly or downwardly along the uprights. The armrests and backrest each include mount sleeves telescopingly slidable along the uprights, each of the mount sleeves including a user-operable adjustment mechanism which includes a lever having a portion thereof selectively engagable with one of a series of holes along the uprights.