Semiconductor　materials　have　gradually　developed　into　attractive　candidate　substrates　for　surface-enhanced　Raman　spectroscopy　(SERS)　due　to　their　unique　characteristics,　exhibiting　great　application　potential　in　a　wide　range　of　scenarios.　The　introduction　of　oxygen　vacancies　plays　a　key　role　in　improving　the　performance　of　semiconductor　substrates　by　effectively　modulating　the　surface　state　and　electronic　structure　of　semiconductor　materials.　Here,　a　reduction　method　is　employed　to　prepare　nonstoichiometric　WO3−x　nanosheets　with　abundant　oxygen　vacancies,　which　as　a　substrate　material　possesses　excellent　SERS　sensing　performance　and　outstanding　signal　reproducibility.　The　presence　of　surface　deficiency　sites　generates　an　effective　photoinduced　charge　transfer　resonance　at　the　interface　between　the　substrate　and　the　analyte　molecules　by　offering　more　charge　transfer　pathways　as　well　as　strong　vibration　coupling,　thereby　achieving　significantly　improved　SERS　sensitivity　on　the　WO3−x　substrate.　Further　investigations　suggest　that　the　defect　structure　is　beneficial　to　facilitate　the　recognition　of　multiple　probe　molecules,　which　indicates　semiconductor　materials　have　great　potential　in　SERS　detection.　©　2022　John　Wiley　&　Sons　Ltd.