Implementing corporate social responsibility (CSR) in supply chains is not a trivial task. In fact, many firms in recent years have publicly proclaimed that in order to keep their CSR commitments, they had to reduce reliance on external suppliers by vertically integrating their operations. Our aim in this article is to examine whether there is truly a relationship between a firm's CSR performance and its level of vertical integration. Drawing on a multi-industry sample of 2,715 firm-year observations, and after addressing endogeneity concerns, we demonstrate that firms with higher CSR performance tend to vertically integrate more (or, outsource less). We also demonstrate that this tendency is weaker for firms that have higher degrees of asset specificity or international diversification. Our core conclusion is that CSR performance and outsourcing are at odds, but firms can reconcile this tension by deepening their collaborations with suppliers.