Ti-Ni and Ti-Ni-Cu shape memory alloy thin films were made by rf magnetron sputtering. The shape-memory behavior associated with the martensitic transformation was measured under various constant applied stresses during thermal cycling from below Mf to above Af. Each strain vs, temperature curve revealed typical single stage deformation behavior. A model based on the thermodynamics of irreversible processes was used for the simulation of the shape-memory behavior of the thin films. Phenomenological material constants that were requisite to the modeling were obtained experimentally. The strain vs. temperature curves calculated by the thermodynamic model, and the experimentally obtained curves, showed a reasonable correspondence in the higher applied stress region, while a large disagreement between them was observed in the lower applied stress region; i.e. the transformation strain was higher in experimental data than in the corresponding calculated data in the lower applied stress region. The present phenomenological macroscopic model was efficient for mean and high stresses where one or two variants were activated per grain. With lower stresses where four or more variants were activated per grain, our interaction energy expression was not sufficient to describe the multiple interactions between austenite and martensite platelets and between martensite variants.