A roll formed step rail for a vehicle comprises an elongated rail body including a continuous rail wall of substantially uniform thickness. The rail wall describes a continuous cross-sectional profile between two elongated free edges, the cross-sectional profile of the rail being substantially uniform along the length of the rail body. The cross-sectional profile of the rail body includes a relatively flat top portion disposed between a substantially semi-circular front curved portion and a substantially quarter-circular rear curved portion. A rear mounting lip extends forward from the rear curved portion to one of the elongated free edges. A front mounting lip extends upward and then rearwards from the front curved portion to another of the elongated free edges. The elongated free edges are generally in line with one another, but spaced apart to define a longitudinal channel therebetween having a predetermined width. The rail body is formed from a sheet of material by a process of roll forming.