This　paper　presents　a　life　cycle　cost　model　for　systems　subject　to　multiple　dependent　degradation　processes　and　environmental　influence.　Different　from　most　existing　studies　that　assume　an　infinite　time　horizon　for　cost　analysis,　we　evaluate　the　life　cycle　cost　within　a　finite　horizon.　The　system　is　subject　to　multiple　degradation　processes,　among　which　the　dependence　is　described　via　copula.　In　addition　to　the　stochastic　dependence　of　the　degradation　processes,　the　health　condition　of　the　system　is　influenced　by　the　operating　environment.　The　environmental　influence　on　the　system　condition　lies　in　two　aspects:　It　accelerates　or　decelerates　the　degradation　processes　and　meanwhile　leads　to　a　random　failure　threshold.　System　reliability　considering　multiple　dependent　degradation　processes　and　environmental　influence　is　assessed　as　the　first　step,　followed　by　the　life　cycle　cost　analysis.　A　numerical　example　is　presented　to　illustrate　the　proposed　model.　©　2020　Elsevier　Ltd