Magnetic shape memory alloys (MSMAs) are a class of materials that exhibit large, recoverable inelastic strain. After cooling from austenite to martensite, MSMAs have a tetragonal crystalline structure with three possible orientations called variants. These variants can rotate as a result of applied stress or applied magnetic field and the resulting inelastic strain can be as high as 10% . To effectively use MSMAs in any potential application, a model that can accurately predict the magneto-mechanical behavior of the MSMA is required. Kiefer and Lagoudas developed a thermodynamic basis for modeling MSMAs and then apply it in the case where two of the three martensitic variants exist . The improvements to the Kiefer and Lagoudas model proposed in this paper include a different analysis of the demagnetizing effect and an inclusion of the resulting axial demagnetizing field.