Understanding　the　interfacial　segregation　behavior　in　V-doped　WC-Co　hard　metals　is　necessary　to　demystify　the　effect　of　dopant　on　microstructural　evolution　and　mechanical　properties.　Herein,　aberration-corrected　scanning　transmission　electron　microscopy　was　utilized　to　investigate　the　atomic　level　segregation　mechanism　at　WC-Co　phase　boundaries　and　WC　grain　boundaries　in　V-doped　WC-Co　composites　systematically.　A　key　finding　is　that　the　segregation　behavior　largely　depends　on　the　orientation　of　low-index　planes,　particularly　the　basal　and　prismatic　facets　that　prevail　in　WC-Co.　V　solute　atoms　show　a　relatively　weak　segregation　at　the　WC　prismatic　plane-terminated　interfaces,　occurring　largely　within　a　monolayer　with　∼10　at%　V　at　the　outermost　surface.　In　contrast,　segregation　at　the　basal　facets　of　WC　grains　distributes　within　a　bilayer　with　a　higher　concentration　of　∼25　at%.　Additionally,　this　study　shows　that　the　facet-dependent　interfacial　segregation　behavior　is　universal　for　both　phase　boundaries　and　grain　boundaries,　which　often　have　at　least　one　basal　or　prismatic　WC　facet.　Our　study　presents　a　general　solute　segregation　mechanism　at　an　atomic　level　and　demonstrates　that　the　terminal　planes　of　interfaces　determine　the　atomic　structure　and　segregation　profile,　while　the　interfacial　orientation　has　little　influence.　©　2021