A collapsible bed frame that supports a box spring includes side rails and telescoping cross rails. A first hinge connects upper and lower portions of a first side rail that are each at least 35 inches long. A first portion of a cross rail telescopes inside a second portion of the cross rail, and the first portion is connected to the first hinge. Upper and lower portions of a second side rail are connected by a second hinge that includes a slot. The second portion of the cross rail has a tongue that fits into the slot on the second hinge. The side rails also have support legs with flanges that extend above the side rails when the support legs are extended. The first and second hinges also include flanges that together with the support leg flanges prevent the box spring from sliding towards either side of the bed frame.