Abstract: A concrete forms assembly for casting a concrete stair and comprising two tiers of panels of sheet material, each panel being channel shaped in cross section. Each tier of panels comprises a pair of opposite side panels and a front panel bridging ends of the side panels, and the side panels of the second tier are shorter than the side panels of the first tier so as to leave an exposed space to define a first or intermediate step of the stair. Clips are swingably disposed on the upper flange of each of the side panels in the lower tier to engage with the lower flanges of the front panel in the second tier, and hooks are carried by the upper flanges of each of the side panels for connecting the upper flanges of the front panels to the front panels in the respective tiers.