Abstract: A foldable ladder is disclosed having a central and two outer parallel support members or "stiles" and a plurality of steps connected between the central and the outer stiles. Each step is arranged to fold between an erected position, in which it extends generally at right angles to the longitudinal direction of each stile to which it is connected, and a storage position in which the step lies generally parallel to the central stile with the outer stile to which it is connected extending parallel to and in close juxtaposition wit the central stile. Engaging means are provided adjacent the upper end of the central stile for holding cooperating engaging means of a supporting member such as another ladder section (forming an extension ladder) or a prop extending to ground (forming a step ladder). Finally, at least one strut is arranged on each side of, and extends outwardly from, the central stile to support the steps and outer stiles when the latter are in the erected position.