Nickelphosphide, a Ni-dominant member of the join Ni3P–Fe3P, is the second most abundant phosphide in nature, after its Fe-counterpart, schreibersite Fe3P. Surprisingly, the Fe-Ni distribution in the crystal structure of natural nickelphosphide has never been studied. In this paper, we present the results of X-ray single-crystal study of 13 nickelphosphide samples from different meteorite groups: irons, pallasites (both the main group and the Eagle Station), mesosiderites, and the recently established achondrite grouplet, tissemouminites. The Ni content varies from 1.52 apfu (atoms per formula unit), or 50.6 mol.% Ni3P, in the mineral from the tissemouminite Northwest Africa 1054 (NWA 1054), to 1.87 apfu ≡ 62.3 mol.% Ni3P in phosphide from the Hainholz mesosiderite. The Fe/Ni distribution over the M1, M2, and M3 sites of the crystal structure exhibits a sharp Fe-Ni ordering, with Ni always predominating at the M3 and M2, leaving the M1 site Fe-dominant even in the Ni-richest varieties. This ordering implies that the ideal end-member formula of meteoritic nickelphosphide is Ni2FeP, rather than the currently adopted Ni3P. Consequently, the minerals of the considered series can be represented by three different species, with the end members Fe3P, Ni2FeP and Ni3P