A cart suitable for supporting a grill, including a firebox. The cart has four panels each of which has all four of its edges bent to form a flange that provides structural rigidity and a connection feature for facilitating the assembly of the cart. Two opposing side panels are carried by and preferably welded to a respective side frame. The side frames are joined by upper crossbars, one at the front of the cart and a second at the rear of the cart. A bottom panel fits into and is carried by troughs formed by upturned lips on the lower edges of the side panels. The structural integrity and racking strength of the cart is enhanced by the attachment of a rear panels, which has a lower lip that locks into engagement with the rear edge of the bottom panel. The top edge of the rear panel is fastened to the rear upper crossbar to complete the basic structure of the cart. Hooks welded to the side frames allow easy and secure attachment of side and front attachments to the cart.