This article examines an action research project on inter-faith dialogue within the sensitive context of Catholic pupils being taught Catholic religious education in state-funded secondary schools. Twenty pupils in S3 and S4 (Year 10 and Year 11) participated in a series of three paired conversations that focused primarily on science and religion, values and historical evidence. Their conversations were analysed quantitatively and qualitatively with regard to the dialogic skills of cumulative talk and exploratory talk, and deep learning in religious education. The pupils displayed high levels of engagement with both cumulative and exploratory talk; and statistical analysis through a chi-square test indicated a significant amount of deep learning occurring. This article concludes that inter-faith dialogue can promote the development of both cumulative talk and exploratory talk amongst secondary school pupils. Such dialogue also provides opportunities for peer teaching, critical reflection and deep learning.