The effect of heat treatments on an as-HIPed ?-TiAl intermetallic alloy was examined. Duplex and fully lamellar microstructures were generated by annealing and subsequently characterized. The relationship between the microstructures and the deformation mechanisms of the intermetallic alloy was studied by means of in-situ tensile experiments performed at 580 ºC and 700 ºC inside a scanning electron microscope (SEM). In addition, electron backscatter diffraction (EBSD) was performed before and after straining. The incidence of the different deformation mechanisms was analyzed based on the observation of the evolution of the microstructure and the texture with straining.