Abstract The wear of both as-cast and annealed nanostructured Fe30Ni20Mn20Al30, which consists of fine alternating B2 (ordered b.c.c.) and L21 (further ordering B2) phases, was studied using pin-on-disk tribotests in three different test environments, oxygen, air and argon. The counterface in all tests was yttria-stabilized zirconia. It was found that the annealed alloy showed better wear resistance than the as-cast material, probably because the annealed Fe30Ni20Mn20Al30 has both a higher hardness and better ductility. The wear was reduced dramatically by the removal of the oxygen from the test environment. The zirconia counterface showed similar wear behavior in all environments. The tips of the wear pins were examined using a combination of X-ray diffractometry, scanning electron microscopy and transmission electron microscopy, the latter using specimens produced by focused ion beam milling. A considerable number of cracks and pits were present on the worn surface of pins tested in oxygen-containing environments, while a relatively smooth mixed layer and plastic flow were evident on the worn surface of pins tested in argon. Both two-body and three-body abrasive wear, as well as deformation and delamination, contributed to the wear.