As past research has identified frontline employees as the primary communicators of a company's CSR, this paper reports on a large-scale quasi-field experiment aimed at gaining a deeper understanding of the levers of successful in-store, pointof-sale, CSR communication. In cooperation with a large international retailer, the authors analyzed the effects of varying in-store CSR communication strategies in 48 unique stores, combining data from a customer survey (N = 38,999), company records of customers' real visits and purchases, and interviews with store managers. Taking into account the nested structure of the data, the authors reveal that CSR-related training of frontline employees bestows its favorable effect on customers and customer behavior only if it is accompanied by the store managers' personal support for CSR.