The interaction of the halogens, iodine, bromine and chlorine with a tungsten (100) surface has been studied by ultraviolet photoelectron spectroscopy. The three halogens produced a series of very high intensity adsorbate spectra with many similarities. Variation of exposure and temperature produced three identifiably different spectral types for bromine and chlorine and two for iodine. These did not coincide with the discontinuities in the observed work function changes. The spectral types are identified with changing surface structures frequently observed with halogen adsorption as increasing adsorption forces the overlayer to compress. The adsorption is considered to be wholly atomic.