The electronic structure of the InAs( 111 )1 × 1 surface has been investigated by angle resolved photoelectron spectroscopy along the symmetry lines Γ K , Γ M , and Γ M ′ of the surface Brillouin zone. The bulk valence band structure was calculated using a combination of the linear augmented plane-wave method and the relativistic augmented plane-wave method. We have projected the theoretical bulk band structure onto the surface Brillouin zone to separate surface states from surface resonances. Two surface related structures, S 1 and S 2, have been observed and their E i( k ‖) dispersions are established. Both S 1 and S 2 show the symmetry of the 1 × 1 surface Brillouin zone, which is consistent with the observed 1 × 1 LEED pattern. We identify S1 as the As-derived dangling bond state, and S 2 is associated with the backbonds connecting the As atoms in the surface layer with the underlying In layer.