The influence of religious groups in democratic policy making has often been a source of political controversy. In the United Kingdom, the legalization of same‐sex marriage in England and Wales may in some ways be thought to exemplify the weakening social position and policy power of the churches. Drawing on a mixture of methods—including analysis of newspaper coverage, legislative debates, and policy documents, plus interviews—this article assesses the extent to which Christian interest groups achieved different forms of policy‐related influence, and its dynamics. It finds that, despite important failures, these groups nonetheless achieved various types of success, including over the policy debate, small policy shifts, and "counteractive" influence, reflecting both the weaknesses and persisting strengths of Christianity within British society. The findings are likely to have wider implications for understanding the policy strengths of religious actors in similar contexts of socio‐religious change elsewhere. Related Articles: Bramlett, Brittany H. 2012. "The Cross‐Pressures of Religion and Contact with Gays and Lesbians, and their Impact on Same‐Sex Marriage Opinion." Politics & Policy 40(1): 13–42. https://doi.org/10.1111/j.1747‐1346.2011.00337.x. Ledet, Richard. 2017. "Sorting the Left from the Rest: The Communitarian Religious Perspective and Liberal Economic Attitudes." Politics & Policy 45(6): 1051–79. https://doi.org/10.1111/polp.12238. Tubadji, Annie. 2023. "You'll Never Walk Alone: Loneliness, Religion, and Politico‐Economic Transformation." Politics & Policy 51(4): 661–95. https://doi.org/10.1111/polp.12538. [ABSTRACT FROM AUTHOR]