The aim of this paper is to present an overview of the tensile behavior of ultrafine grained Mg-3%Al alloy. The bulk ultrafine grained Mg alloy was synthesized via consolidation of mechanical alloying. The grain size of the sample was calculated from X-ray diffraction line profile analysis. Tensile properties of ultrafine grained samples tested at temperatures of 25°C to 250°C are compared with that of a coarse grain microcrystalline sample. Plastic deformation of the ultrafine grained sample exhibits a combination of work hardening (15–48% plastic strain) and perfect plastic behavior characterized by a constant flow stress. At room temperature, the sample showed a gain in strength of about two times and enhanced ductility compared to the microcrystalline sample. The strain rate sensitivity was observed to be three times higher in the present ultrafine grained sample. A stress drop with increasing test temperatures was observed in both the samples. The effect of temperature on flow behavior in terms of work hardening rate, temperature sensitivity, ductility, yield strength, and tensile strength are also examined precisely. The present results show important evidence of the temperature dependence of the mechanical properties of the ultrafine grained Mg-3%Al alloy in comparison to the microcrystalline sample.