We present an investigation of the band offsets in amorphous/crystalline silicon heterojunctions (a-Si:H/c-Si) using low energy photoelectron spectroscopy, ellipsometry and surface photovoltage data. For a variation of deposition conditions that lead to changes in hydrogen content and the thereby the a-Si:H band gap by ∼180 meV, we find that mainly the conduction band offset ΔE
V varies, while ΔE
C stays constant within experimental error. This result can be understood in the framework of charge neutrality (CNL) band lineup theory.