Political realism is often seen as vulnerable to the “Machiavellian temptation,” that is, to the bracketing out of moral principles in the conduct of statecraft. In this article, I explore the use of Thomist themes in the writings of Martin Wight (1913–1972), a seminal figure of the so-called English School of international relations theory. Scholars have commented on the Christian realist roots of the English School, but it is little noted that Wight's most famous essay, “Western Values in International Relations,” uses the language of Thomism. By exploring the use of Thomist concepts in Wight's thought and the parallels to be found in the thought of his contemporary, Thomist political philosopher Jacques Maritain, I show how he seeks to escape the realist temptation to Machiavellianism. I then go on to sketch out the possible shortcomings of this approach.