Studies were conducted on the chemisorptive and magnetic properties of supported nickel catalysts in order to investigate the effect of metal-support interactions on different support materials. The catalysts consisted of both 7 and 20% nickel supported on SiO 2, Al 2O 3, TiO 2, alumina-aluminum phosphate (AAP), and magnesia-alumina-aluminum phosphate (MgAAP). For catalysts supported on phosphate-containing materials, the inducement of metal-support interactions was accompanied by both a lowering of the Curie temperature and a change in chemisorptive behavior. Irreversible hydrogen chemisorption was suppressed, as is typical of strong metal-support interactions (SMSI) materials, but a significant reversible chemisorption was still evident. In contrast, the inducement of SMSI in TiO 2-supported catalysts showed no change in Curie temperature and no reversible hydrogen chemisorption. The different behaviors observed in the various materials have been attributed to different mechanisms responsible for the inducement of the metal-support interactions.