Abstract: A collapsible chair that includes a front pair and rear pair of crossed, pivotally interconnected legs having a common pivot axis extending from front to rear, seat-supporting rails extending between the pairs of legs front to rear at each side with such seat-supporting rails secured to the uppermost portion of each leg and inwardly thereof, unitary armrest and backrest supporting structure extending between the pairs of legs front to rear at each side by pivots securing same to the uppermost portion of each respective leg only, so as to be swingably separable from the adjacent inner seat-supporting rail and to move into substantial upstanding abutment thereagainst in chair-defining relation, with each unitary armrest and backrest supporting structure including a reinforcing member projecting inwardly thereof moving into and out of overlying engagement with the uppermost surface of the adjacent inner seat-supporting rail.