The site preference of early 3d (Ti, V), 4d (Zr, Mo) and 5d (Hf, Ta, W) transition metal elements in C15 NbCr 2 Laves phase was studied using first-principles calculations. According to the present calculations, at T = 0 K, Zr, Hf and Ta consistently have a preference for the Nb sites in Nb-rich, Cr-rich and stoichiometric NbCr 2, while the site preference of Ti, V, Mo and W varies strongly with alloy composition. Using a statistical–mechanical Wagner–Schottky model based on the canonical ensemble, the finite temperature site occupancy behavior of those transition metal elements in NbCr 2 was further predicted. It was found that the site preference of Ti, V, Mo and W also depends strongly on temperature. The calculated results compare favorably with the experimental measurements using ALCHEMI and synchrotron X-ray diffraction techniques.