Abstract Scholars of the classical American philosophical tradition have not written much about prayer, despite the fact that almost every single one of the major figures of this tradition acknowledged its significance. The gap in the literature is notable in the case of George Santayana, who discusses prayer in several of his major works. And of all the classical American philosophers, Santayana may have the most fully developed treatment of prayer, particularly as it relates to the problem of petitionary prayer. Yet his account of payer has not received much attention. This is surprising since, on the one hand, many of Santayana’s other views on religion and spirituality have been widely commented on, and, on the other hand, prayer has been a prominent topic in philosophy of religion in recent decades. And it makes sense for scholars of the classical American tradition nowadays to consider Santayana’s views about prayer, at the least because this tradition concerns itself with the problems of ordinary people, and to most Americans–and even to some atheist Americans–prayer seems to matter a great deal. Santayana’s treatment of prayer can be organized into two phases. First, he offers a twofold case against the common view that petitionary prayer is materially efficacious–that is, the view that petitionary prayer can do something to affect whether God brings about a desired state of affairs that would not have otherwise obtained had the request for it not been made.