This paper reports the spectral responses of the steady-state and modulated photoconductivity in undoped gamma-Ce2S3 single crystals and pressed powder pellets and the modulated photoconductivity in doped gamma-[Na]Ce2S3 (Na/Ce = 0%, 5%, 12%, and 20%) pressed powder pellets. Their analysis clearly indicates the presence of several levels between the valence and conduction bands. Taking into account the temperature dependence of the spectral responses and the electron lifetimes that could be estimated, a band structure model is proposed for gamma-Ce2S3 sesquisulfide, discriminating between defect levels and cerium 4f levels. The influence of the substitution/insertion of sodium on the electronic structure is also discussed.