This paper addresses a multiscale strategy for the prediction of anhysteretic magneto-elastic behavior and its application to the definition of a magneto-elastic constitutive law for Terfenol-D. The multiscale modeling is based on an energetic procedure at the single crystal scale. Localization and homogenization procedures are then applied to deduce the constitutive law of polycrystalline media from the behavior of the corresponding single crystal. The method is applied first to define the magneto-elastic behavior of single crystals, and the application to polycrystalline samples is then considered. Modeling results are compared to experimental data.PACS. 75.80.+q Magnetomechanical and magnetoelectric effects, magnetostriction -46.25.Hf Thermoelasticity and electromagnetic elasticity (electroelasticity, magnetoelasticity)