This article examines the role of the Pentecostal Evangelical movement in the success of the ‘No’ campaign in the Colombian peace plebiscite of 2 October 2016, where Colombians voted to reject the peace agreement which had been reached between the Colombian government and the Armed Revolutionary Forces of Colombia (FARC). It discusses the reasons that motivated large sectors of the Evangelical electorate to oppose the agreement, paying particular attention to the success of the argument that the agreement was contaminated with what Pentecostals termed ‘gender ideology.’ In terms of methodology, the article draws on a variety of sources, including interviews, field observation and written sources both scholarly and popular, including press and Internet articles. We track how ‘gender’ comes to be shorthand for the host of social ills with which it was associated during the debates around the Colombian peace plebiscite through use of the term ‘gender ideology’. We posit that it is the links between ‘gender’ modernity, colonialism and the development industry, its academic, value-neutral quality and its status as an isolated technical term that allow ‘gender’ to become a proxy for a wide range of social dissatisfactions. We conclude that the success of the ‘No’ campaign was possible due to the convergence of several sectors of society, particularly between the political right and a social movement which, inspired by religious values, opposed the recognition of LGBTI (Lesbian, Gay, Bisexual, Transgender and Intersex) rights and the use of the term ‘gender’ in the agreements.