PURPOSE: Understanding sustainable employability (SE) of people with limited capability for work (LCW) due to physical or mental disability is crucial for the sustainable participation of this target group. Therefore, adequate measurement instruments for SE are needed. This study aims to validate a questionnaire to measure SE among people with LCW using a participatory approach, including person-job fit (PJ fit) and work-related sense of coherence (Work-SoC). METHODS: Existing scales for the main concepts were tested and adapted for face validity via cognitive interviews (n = 6), with the involvement of a co-researcher with LCW in the research team. Next, the questionnaire was administered among people with LCW (n = 248) to assess its factor structure (Confirmatory Factor Analysis) and reliability (Cronbach's alpha). RESULTS: Analysis of the cognitive interviews identified problems with clarity and readability of items, instructions and response categories of used (existing) scales. The main adjustments concerned the shortening of text length, the usage of familiar language and examples, and the addition of an introduction game. Most of the adapted SE indicator scales showed an overall good fit and acceptable-to-good internal reliability. The overall SE model had an overall good fit, and excluding 'internal employability' further improved this fit. PJ fit and Work-SoC had an acceptable/good model fit and internal consistency. CONCLUSION: The participatory validation process resulted in a validated and comprehensive questionnaire to measure SE, PJ fit and Work-SoC among people with LCW, which enables research into the development of their SE. This questionnaire can be utilised to contribute to a more inclusive labour market.