The aim of the paper is to explore teachers' methods of delivering an ethos of tolerance, respect and mutual understanding in one integrated secondary school in Northern Ireland. Drawing on interviews with 18 teachers in the school, it is argued that most teachers make 'critical choices' which both reflect and reinforce a 'culture of avoidance', whereby politically or religiously contentious issues are avoided rather than explored. Although teachers are well-intentioned in making these choices, it is shown that they have the potential to create the conditions that maintain or even harden psychological boundaries between Catholics and Protestants rather than dilute them.