We have used Auger electron spectroscopy (AES) combined with Ar+sputtering to profile the chemical composition of UHV‐cleaved InP(110) interfaces with Au, Al, Cu, Ni, Ti, and Ag films. We observe pronounced anion and cation segregation to the free metal surface which depend sensitively on the metal–InP reactivity. Reactive metal (e.g., Al, Ti, or Ni) interlayers at Au–InP interfaces decrease anion diffusion and surface segregation monotonically with increasing interlayer thickness and AES depth profiles indicate a P accumulation at or just below the intimate metal–InP interface. These and other sputter‐AES studies suggest that the lower (higher) Schottky barriers of reactive (unreactive) metals are associated with cation (anion) depletion within the InP bulk and on anion accumulation at the intimate InP–metal interfaces.