During attempts to roll Fe-18.7%Ga alloy (atomic%), an alloy of interest because single crystal samples exhibit magnetostriction of ∼400 ppm, cracks formed along grain boundaries and subsequently samples fractured during hot rolling such that the alloy was too brittle to make thin sheets. While variations to rolling schedules (temperatures, times, roll diameters, etc.) may improve rollability, in this paper we investigate the effect of boron addition on Fe-18.7% Ga alloy magnetostrictive and mechanical properties. Thin sheets of Fe-18.7%Ga alloy plus 0.5 and 1.0 at.%B were successfully fabricated to thickness of 0.35 mm using rolling processes. It was observed that the fracture surface of the B-free alloy clearly appeared as an intergranular fracture mode and that of the B-added alloys was changed to a transgranular fracture mode with grain refinement. The annealed sheets with boron content of 0.5 and 1.0 at.% exhibit the maximum magnetostriction values of 103 and 184 ppm, respectively. In the case of Fe-18.7%Ga plus 1.0 %B, Fe2B phase presents throughout the α-iron matrix in small amount.