The band alignment at the interface of a SnO2/gamma-In2Se3 heterojunction has been studied by XPS. The measurements have been performed on samples obtained under the same experimental conditions as those used to achieve the SnO2/gamma-In2Se3 rectifying contact. The gamma-Ln(2)Se(3) upper layer was 5 nm thick. The semi-direct XPS technique used to measure the band offsets allows us to estimate the conduction band discontinuity Delta Ec to -0.3 +/- 0.3 eV.