The state-of-the-art density functional theory is used to investigate various properties of rare- earth based inverse perovskites Gd3AlX (X = B, N). The materials show robust structural stability at high pressures without undergoing any phase transition. The ferromagnetic character is retained at high pressures with high value magnetic moments 7.09 mu(B) and 7.38 mu(B) at 0 GPa for Gd3AlB and Gd3AlN, respectively. In view of Poisson's and Pugh's ratio, the ductility and brittleness of Gd3AlX (X = B, N) has been analyzed. The mechanical stability is maintained throughout the pressure range with high value of Debye temperature. Transport properties have been calculated at different pressures for both the alloys, which show excellent thermoelectric properties. Besides, this the variation on some significant thermodynamic properties is also studied. Our successful prediction of the stabilization of the metallic Gd3AlX (X = B, N) has proposed a route to synthesize novel rare-earth-based inverse perovskites.