Drawing on the job demands-resources (JD-R) model, we investigated how formal mentoring influences proteges work-to-family conflict (WFC). With a sample of 193 proteges in ongoing formal mentoring programs, we found that the extent of formal mentoring functions received was associated with proteges WFC in two ways. On the one hand, the extent of formal mentoring functions received was positively related to job resources, which in turn negatively related to proteges WFC. On the other hand, the extent of formal mentoring functions received positively predicted job demands (i.e., workload), which subsequently had a positive association with proteges WFC. Furthermore, proteges work-family centrality moderated the above dual paths such that the indirect effect of the extent of formal mentoring received on proteges WFC via job resources was stronger for proteges who value work more important than family, whereas the indirect effect of the extent of formal mentoring received on proteges WFC via workload was stronger for proteges who value family more important than work. Implications for research and managerial practices are discussed. (C) 2017 Elsevier Inc. All rights reserved.