The　literature　has　predominantly　focused　on　the　positive　effects　of　leader　boundary-spanning　behavior,　but　its　potential　costs　should　also　be　given　serious　consideration.　Drawing　from　the　work-home　resources　model,　we　investigated　the　ways　in　which　boundary-spanning　behavior　influences　both　boundary-spanning　leaders　themselves　and　their　spouses.　Using　daily　diary　data　collected　from　75　matched　couples　in　China　over　10　consecutive　workdays,　we　performed　a　multisource,　multilevel　research　design.　The　results　suggest　that　leader　boundary-spanning　behavior　appears　to　have　positive　relationships　with　leaders’　work-to-family　conflict　and　their　spouses’　perceived　family　incivility　via　ego　depletion.　We　also　found　that　two　related　factors　–　boundary-spanning　self-efficacy　and　manager　support　for　boundary-spanning　behavior　–　play　significant　mitigating　roles　in　this　context.　These　results　suggest　that　effort　is　needed　to　balance　the　benefits　of　leader　boundary-spanning　behavior　with　the　corresponding　challenges,　including　individual　depletion　and　detrimental　family　outcomes.　©　2022　Elsevier　Inc.