Purpose This study aimed to develop a questionnaire measuring preventive behaviors at work. Methods A three-step design, including qualitative and quantitative methods, was followed: (1) item generation, (2) experts’ validation of content, and (3) pretesting. Results For step 1, 49 relevant existing scales were reviewed, and a pool of 172 items was generated. Redundant items were deleted (n = 48), and unclear items were reworded (n = 27). For step 2, 14 experts (five occupational therapists, four researchers, and five workers) assessed the representativeness, relevance, and clarity of each item through content validity indices (CVIs). An average overall CVI of 0.97 was obtained, and 87.5% of the experts stated that the questionnaire was comprehensive. During this step, 63 items were deleted, and 35 were modified. For step 3, the tool was pretested in the clinical settings of four dyads (occupational therapist–worker). The thematic analysis of interview content allowed several changes to be made to the questionnaire, including the addition of information and format changes. Conclusions Overall, this three-step study led to the construction of a 61-item French questionnaire entitled the Échelle de fréquence des comportements préventifs au travail Frequency Scale of Preventive Behaviors at Work. In rehabilitation settings, this tool could be useful to support professionals in enabling workers to adopt preventive behaviors, thereby fostering a healthy, sustainable return to work after a disability period. However, further metrological property assessment is required. A validating study using a large pool of workers is ongoing.