Partner opportunism, Relational learning, TSI, Mutual hostages, Payoff inequity, Cultural diversity, Goal incompatibilities The purpose of this study is to investigate determinants of partner opportunism in Korean discount store distribution channels. In addition, this study also try to examine moderating role of relational learning in the relationship. This study deals with transaction specific investment asymmetry, mutual hostages, payoff inequity, cultural diversity, and goal incompatibilities as determinants of partner opportunism. For empirical testing, 293 respondents of suppliers of discount store in Korea were surveyed and the analysis utilizing partial least square model indicated that TSI asymmetry, payoff inequity, and goal incompatibilities had positive effects on partner opportunism. On the other hand, mutual hostages had negative effect on partner opportunism. In addition, relational learning had moderating effect on the relationship between TSI asymmetry, mutual hostages, and payoff inequity and partner opportunism.