Although family–supportive supervision (FSS) has been identified as one of the most useful social resources for reducing the occurrence of work interference with family (WIF), relatively little is known about the boundary conditions and the underlying mechanisms through which this relationship occurs. Drawing on conservation of resources (COR) theory, we examined how and when FSS relates to WIF in two field studies, focusing on family–role overload as a moderator and employee task crafting as a mediator. Results from Study 1, using multi-wave data from a high-technology firm, showed that family role–overload moderated the relationship between FSS and WIF such that the relationship was stronger for employees with more family role–overload than for those with less family role–overload. Results from Study 2, using multi-wave data from employees working in different industries, revealed that employee task crafting mediated the interactive effect of FSS and family–role overload on WIF. Implications of these findings for research and practice are discussed. [ABSTRACT FROM AUTHOR]AB- Copyright of International Journal of Human Resource Management is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder’s express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.