Banks play a predominant role in the economy and are subject to growing expectations from stakeholders. It is therefore important to understand the financial impact of CSR on banks' activities. This article examines the impact of CSR on bank efficiency by using a DEA Dynamic Network Model. Based on an international sample of 184 banks in 41 countries over the 2009-2015 period, our empirical investigation reveals a positive impact of CSR on bank efficiency. We further show that this relationship is contingent upon the institutional context. Specifically, we find that CSR has a positive impact on bank efficiency only in developed countries, in countries where investor protection is high and in countries featuring a high degree of stakeholder orientation. We thus assert that some institutional characteristics must be present for the positive impact of CSR on bank efficiency to materialize.