Abstract: A high tensile strength, hot or cold rolled steel sheet having improved ductility and hole expandability consists essentially, on a weight basis, of: C: 0.05-0.3%, Si: 2.5% or less, Mn: 0.05-4%, Al: greater than 0.10% and not greater than 2.0% wherein 0.5.ltoreq.Si(%)+Al(%).ltoreq.3.0, optionally one or more of Cu, Ni, Cr, Ca, Zr, rare earth metals (REM), Nb, Ti, and V, and a balance of Fe and inevitable impurites with N being limited to 0.01% or less. The steel sheet has a structure comprising at least 5% by volume of retained austenite in ferrite or in ferrite and bainite. A hot rolled steel sheet is produced by hot rolling with a finish rolling end temperature in the range of 780.degree.-840.degree. C., cooling to a coiling temperature in the range of 300.degree.-450.degree. C. either by rapid cooling to the coiling temperature at a rate of 10.degree.-50.degree. C./sec or by initial rapid cooling to a temperature range of 600.degree.-700.degree. C.