Metal orthoniobates are promising candidates for energy applications, such as solid oxide fuel cells, due to their excellent proton conductivity and high thermal stability. Among these, lanthanum niobates (LaNbO4) are particularly notable for their reversible ferroelastic transition from monoclinic fergusonite (I2/b) to tetragonal scheelite (I41/a) upon heating or chemical doping. In this study, we synthesized vanadium-doped ANbO4 (A = La, Y, Nd) using the conventional solid-state method. The lattice parameters were determined through X-ray powder diffraction at room temperature. Our results indicate that vanadium solubility and the lattice parameters are independent of the A-site cations. Notably, lanthanum niobates exhibit high vanadium solubility and a ferroelastic phase transition at room temperature. The observed increase in the monoclinic phase volume of lanthanum niobates is particularly intriguing, considering the smaller ionic radius of pentavalent vanadium compared to pentavalent niobium. Furthermore, vanadium doping has distinct effects on the lattice parameters of yttrium and neodymium orthoniobates, underscoring the differential influence of vanadium ions in these structures.