There are two marketing capabilities situated at the product-market interface: customer management (CM) and new product development (NPD). Both are ambidextrous given they involve exploitation and exploration, yet important questions remain unanswered. Is it beneficial to have higher combined levels of exploitation and exploration? Or should these be balanced? What internal and external factors might influence these two forms of ambidexterity? This study examines these issues using data from a sample of U.S. manufacturers. We find that entrepreneurial orientation (EO) differentially affects the exploration-exploitation balance within CM and NPD, in dynamic environments. Performance improves when there is higher combined ambidexterity in both CM and NPD; it suffers when NPD ambidexterity is imbalanced by an emphasis towards exploration. CM can be similarly imbalanced yet has no adverse impact. A moderated mediation analysis reveals that EO has both positive and negative associations with performance under different environmental conditions. © 2018