A chair includes a backrest swivel mechanism that is configured to permit the backrest to swivel about a vertical axis about a preselected range of motion. The backrest may be configured to swivel, or rotate, about a vertical axis that is defined by an element located adjacent a rearward central location that is below the seat of the chair and adjacent a rear of the chair. A lock mechanism can be selectively engaged to lock and unlock the swiveling mechanism so that when in the locked state, the backrest cannot swivel and when in the unlocked state, the backrest can swivel. In some embodiments, the range of swiveling motion may be with a predefined range, such as +/−10° or +/−20° of rotation relative to a central position of the backrest.