Galfenol, Fe100−xGax (∼5<x<∼20), is a unique magnetostrictive alloy that combines high saturation magnetostrictions with robust mechanical properties. [Clark et al., “Magnetostrictive properties of body‐centered cubic Fe‐Ga and Fe‐Ga‐Al alloys,” IEEE Trans. Magn. 36, 3238 (2000)]. These materials can be welded and machined. Additionally, alloys treated with a stress annealing process retain the maximum value of magnetostriction up to tensile loads of approximately 38 MPa. [Wun‐Fogle et al., “Stress annealing of Fe‐Ga transduction alloys for operation under tension and compression,” J. Appl. Phys. 97, 10M301 (2005)]. Room temperature Fe81Ga19 single crystal properties are Ms≅1.7 T, (3/2)λ100≅400×10−6, c′≅20 GPa, and tensile strength >500 MPa. In this presentation, temperature, field and stress dependent magnetic and elastic properties such as permeability, piezomagnetic d constants, Young’s modulus and coupling factors will be presented for several Fe–Ga alloys.