This　study　examines　the　spatial　effects　of　economic　complexity　on　carbon　emissions　in　82　countries　from　2001　to　2019　based　on　a　spatial　panel　model.　Our　research　explores　the　spatial　mediating　roles　of　energy　structure　and　energy　efficiency,　considering　both　local　and　spillover　effects.　We　find　economic　complexity　has　a　positive　local　effect,　but　a　negative　spillover　effect　on　carbon　emissions.　The　positive　local　effect　is　more　potent　in　countries　with　high　economic　complexity　compared　to　low　ones.　Economic　complexity　promotes　local　carbon　emissions　by　curbing　local　energy　structure　but　limits　the　carbon　emissions　of　neighbours　by　boosting　their　energy　efficiency.　This　study　enriches　the　relevant　achievements　of　the　mechanism　by　which　economic　complexity　impacts　carbon　emissions.　Governments　should　take　advantage　of　the　environmental　benefits　of　economic　complexity,　focus　on　technological　improvements　and　green　production,　optimize　the　energy　mix　and　promote　energy　efficiency.　©　2024　Informa　UK　Limited,　trading　as　Taylor　&　Francis　Group.