The effect of grain size on the high temperature mechanical behavior of an intermetallic Ti 3 Al compound was investigated. An unusually strong dependence of material ductility on the structural parameter was revealed. Once submicrocrystalline grain size (d < 1 μm) is reached or approached, the superplastic characteristics displayed by Ti 3 Al are considerably higher than those of the intermetallics previously investigated. The most probable reason for such unusual behaviour is that unlike the other intermetallics studied, this compound is not prone to the formation, on heating, of annealing twins which suppress superplastic flow.