An adjustable chair (100; 100') comprising: a lower base member (120; 120') supported by one or more ground engaging members; an upper base member (130; 130') connected to the lower base member (120; 120') by first and second linking members (126-129; 126', 128') each having a first end (126a-129a) connected to the lower base member (120; 120') and a second end (126b-129b) slideably received in corresponding first and second arcuate tracks disposed in the upper base member (130; 130'); a seat assembly (150; 150') secured to the upper base member (130; 130'); and a chair adjusting mechanism operable to slide the second ends (126b-129b) of the first and second linking members (126-129; 126', 128') within the first and second arcuate tracks to adjust a vertical position of the seat assembly (150; 150') between a lowered position and an elevated position with respect to the lower base member (120; 120'), wherein the first end (126a, 127a) of the first linking member (126, 127; 126') is pivotally connected to the lower base member (120; 120') by a first pivot pin, and the first end (128a, 129a) of the second linking member (128, 129; 128') is pivotally connected to the lower base member (120; 120') by a second pivot pin, and the first and second pivot pins (121, 122) are laterally slideable with respect to the lower base member (120; 120') to permit movement of the first ends (126a-129a) of the first and second linking members (126-129; 126', 128') toward each other when the seat assembly (150; 150') is moved toward the lowered position, and away from each other when the seat assembly (150; 150') is moved toward the elevated position. a lower base member (120; 120') supported by one or more ground engaging members; an upper base member (130; 130') connected to the lower base member (120; 120') by first and second linking members (126-129; 126', 128') each having a first end (126a-129a) connected to the lower base member (120; 120') and a second end (126b-129b) slideably received in corresponding first and second arcuate tracks disposed in the upper base member (130; 130'); a seat assembly (150; 150') secured to the upper base member (130; 130'); and a chair adjusting mechanism operable to slide the second ends (126b-129b) of the first and second linking members (126-129; 126', 128') within the first and second arcuate tracks to adjust a vertical position of the seat assembly (150; 150') between a lowered position and an elevated position with respect to the lower base member (120; 120'), wherein the first end (126a, 127a) of the first linking member (126, 127; 126') is pivotally connected to the lower base member (120; 120') by a first pivot pin, and the first end (128a, 129a) of the second linking member (128, 129; 128') is pivotally connected to the lower base member (120; 120') by a second pivot pin, and the first and second pivot pins (121, 122) are laterally slideable with respect to the lower base member (120; 120') to permit movement of the first ends (126a-129a) of the first and second linking members (126-129; 126', 128') toward each other when the seat assembly (150; 150') is moved toward the lowered position, and away from each other when the seat assembly (150; 150') is moved toward the elevated position.