This paper investigates how internal knowledge dependency and its interaction with external knowledge adoption affect innovation performance in Korean companies. We categorize innovation performance into exploratory innovation and exploitative innovation. Especially, we examine business group effects as group headquarters and sister subsidiaries holistically form the boundary of the firm. Our empirical results first suggest that the degree of internal knowledge dependency is positively associated with exploitative innovation, but negatively with exploratory innovation. Second, internal knowledge dependency is more negatively related to exploratory innovation in independent firms than in business group affiliates. Third, independent firms’ adoption of external knowledge tends to strengthen the positive relationship between internal knowledge dependency and exploitative innovation. Finally, exploitative external knowledge search appears to strengthen the negative relationship between internal knowledge dependency and exploratory innovation in both types of firms.