The role of religion in ethical decision‐making, both for individual managers and at an organisational level, remains elusive due to contrasting findings in extant literature. This is exacerbated by a dearth of studies focusing on specific religious mechanisms that can foster ethical decision‐making, particularly with respect to organisational corporate socially responsible (CSR) behaviour and in backgrounds different from Christianity. This exploratory study investigates the mechanisms in Islam that can influence individual/micro‐ and organisational/meso‐level ethical decision‐making, and hence CSR outcomes. It draws on in‐depth, qualitative data from 63 domestic organisations in Saudi Arabia, the United Arab Emirates and Oman. The findings reveal a complex macro‐normative religious environment, founded on specific factors that shape ethics and decision‐making. Internalised by organisational leaders, these factors translate into organisational CSR behaviour as the organisation becomes a place for fulfilling individual religious responsibilities and even creates CSR products shaped around religious principles. The study contributes to the literature on ethical decision‐making, organisational behaviour and Islamic CSR and offers recommendations for policymakers and practitioners on integrating religion within the organisation.