In Britain, civil society organizations (CSOs) have garnered much praise for promoting interethnic friendships (IEF) and strengthening community cohesion. Yet, there is very little empirical evidence to suggest that participation in CSOs promotes ethnic minorities’ IEF. Using nationally representative longitudinal (2011–2019) and cross‐sectional (2010) data, this article explores the association between participation in CSOs and IEF formation among five British ethnic minority groups and analyses how this relationship is affected by the ethnic composition of CSOs. Overall, fixed effects models show that participation in CSOs only significantly promotes IEF for Indians. For other minority groups it has either no effect or, in the case of Pakistanis, significantly decreases IEF. Further analyses show that compared with ethnic minorities that do not participate in any CSOs, those who participate in mostly interethnic CSOs tend to have significantly more IEF, whereas those who participate in mostly co‐ethnic CSOs tend to have significantly less IEF. Taken together, these findings suggest that the association between civic participation and ethnic minorities’ IEF is much more nuanced than previously thought and policy interventions seeking to improve ethnic integration should, therefore, take the ethnic background of participants and the ethnic composition of CSOs into account.