Anion photoelectron spectra of GaxNy- cluster anions, in which x = 4-12, y = 1 and x = 7-12, y = 2, were measured. Ab initio studies were conducted on GaxNy- cluster anions in which x = 4-7, y = I and Ga7N2-, providing their structures and electronic properties. The photoelectron spectra were interpreted in terms of the computational results. This allowed for identification of the isomers present in the beam experiments for specific GaxN- cluster anions (x = 4-7). The unexpected presence of GaxN2- species is also reported.