Faith schools in England are often regarded as ill-suited to cultivating the abilities, attitudes, and dispositions required for living together harmoniously in an ethnically and religiously diverse society. These concerns might be formulated in terms of the thesis that faith schools in England are considerably sub-optimal for the cultivation of civic virtues compared to the feasible non-faith alternatives. Focusing on one particular civic virtue, namely, tolerance, this article aims to assess this sub-optimality thesis. It identifies a range of factors that might be thought to affect whether a faith school provides an environment that is conducive to the cultivation of tolerance, and then considers the available evidence, both direct and indirect, that bears upon what effect these factors actually have. It argues that the evidence that is available gives insufficient support to the sub-optimality thesis, but it does provide a powerful case for regulating faith schools in various ways.