Islamic religious settings (IRS) may be useful places to implement obesity interventions for Muslims. However, little is known about the level and nature of such activity in these settings. We searched bibliographic databases and grey literature, and requested grey information from Muslim organizations, local councils, and mosques in 13 selected areas in the United Kingdom. Thirty-five interventions were identified; most were poorly described and not evaluated. Twenty-seven interventions focused on physical activity behaviours, four on diet behaviours, one on both behaviours, and seven addressed long-term conditions associated with obesity. Most interventions were led by volunteers from the congregation/faith leaders and were funded through donations from congregants or charity organizations. The evidence suggests that health promotion interventions in IRS have a relatively high reach. Obesity interventions are commonly delivered in UK IRS. Most target physical activity behaviours, are instigated and led by volunteers from the congregation or faith leaders, receive no public funding, and are only recorded in people's memories. High-quality evaluations of well-specified interventions in this context are needed. We suggest that the methods used in this review, including the learning around positionality of researchers, could be adopted by other researchers as a way to locate opportunities for effective community-level interventions.