Influence of the Ga alloying on the crystal structure and parameters of the martensitic transformation are presented. X-ray diffraction has shown the multiphase composition of the samples (β (B2)- phase, γ′ (L12)-phase, (L10)-martensitic phase, Ni5Al3-phase). Metallographic investigations have demonstrated the coarse grain of B2 phase with non-regular needles of Ni3Al and typical martensitic structure. Ga did not suppress the martensitic transformation in NiAlGa alloys. The Ni to Al ratio and quantity of Ga determine the parameters of martensitic transformation.