Abstract: A door sill assembly is provided with an adjustable threshold. A sill assembly is made up of an elongated metal frame for installation on the floor of the doorway. The metal frame is provided with a tongue and sloping sill portion, a vertically extending rib and a shelf located below and integrally oriented relative to the rib. The threshold rail is supported on the frame member shelf portion upon two adjustable feet for varying the relative height level of the rail. A plastic threshold cap is sized to fit over the threshold rail and includes a pair of downwardly spaced ribs sized to securely fit over the vertical rib of the frame member to locate the threshold cap and rail relative to the frame member while providing limited vertical adjustment. Preferably, the interior trim molding is provided which is fixed relative to the frame member and oriented inboard of the threshold cap.