Internal photoemission spectroscopy was used to determine the valence band top energy position in few-monolayer WS 2 and WSe 2 films directly synthesized on top of the SiO 2 insulator. It is found that in WS 2 the valence band top edge lies systematically higher (by 0.4–0.7 eV) in energy than that in WSe 2. This unexpected trend is seen for several synthesis methods suggesting it to be the intrinsic property of these W-based layered dichalcogenides. At the same time, a change in the WS 2 synthesis method from metal sulfurization to chemical vapor deposition leads to a≈ 0.3 eV barrier change indicating a non-negligible impact of interface charges or dipoles. The influence of synthesis chemistry on the WSe 2/SiO 2 interface barrier appears to be marginal at least for the selenization and molecular-beam epitaxy growth methods.