This　paper　investigates　the　relationship　among　zombie　firms,　external　support　and　corporate　environmental　responsibility.　Zombie　firms　refer　to　firms　that　should　go　bankrupt　because　of　low　efficiency　and　profitability　but　survive　with　external　support　from　government　or　bank.　Using　a　sample　of　Chinese　listed　companies　over　the　period　2010–2016,　we　find　that　zombie　firms　have　lower　corporate　environmental　responsibility　performance　than　non–zombie　firms.　Such　an　effect　is　more　pronounced　when　zombie　firms　receive　a　greater　amount　of　external　support　from　government　or　bank.　The　negative　impact　of　zombie　firms　on　corporate　environmental　responsibility　performance　is　stronger　in　heavily　polluting　industries　and　state-owned　enterprises.　To　deal　with　potential　self-selection　and　endogeneity　issues,　Heckman　two-step　estimation　and　propensity　score　matching　approaches　are　used　to　verify　the　validity　of　our　results.　Our　results　are　also　robust　in　the　sensitivity　test　of　changing　measurement　of　zombie　firms.　©　2018　Elsevier　Ltd