People highly involved in their work are likely to experience negative repercussions on other life domains such as family and leisure activities. The purpose of the present study was to identify the potential contribution of passion towards work on work/family interference (WFI) and leisure-time physical activity (LTPA). It was hypothesized that obsessive passion towards work would be positively related to WFI and negatively related to LTPA because it leads to invest more time in one's occupation. Conversely, it was expected that harmonious passion towards work would be negatively related to WFI but positively related to LTPA because it prevents one from devoting a large amount of time to work. A questionnaire measuring WFI, LTPA, passion, and the time spent working weekly was administrated to 160 French teachers. In the first model, path analyses revealed that harmonious passion was positively related to LTPA level, but that obsessive passion and work time were unrelated to LTPA. In the second model, path analyses revealed that work time mediated the positive relationship between obsessive passion and WFI, whereas harmonious passion was negatively related to WFI but unrelated to work time. As a whole, the present study contributes to a better understanding of the work-related predictors of WFI and LTPA.