Thin films of non-stoichiometric indium antimonide (In0.66Sb0.34) of different thickness, 300–1,300 nm, deposited by electron beam evaporation technique on glass substrates have been found to have zincblende structure and of n-type semiconductor as determined by Hall measurements. All the electrical parameters i.e. Hall mobility (μH), carrier concentration (n), resistivity (ρ) and band gap (Eg) have been found to be thickness dependent. Suitable explanations are given in the paper.