The Thomistic influence on the Reformed Scholastics has received a great deal of attention within the last few decades. Authors such as Richard Muller, David Steinmetz, and Carl Trueman have demonstrated continuity between the medieval scholastics, the first generation reformers, and the Reformed scholastics that followed them. While there seems to be consensus that the Reformed scholastic doctrine of God resembles Thomas’s theology proper, more specific claims could be helpful in demonstrating this continuity. This paper will demonstrate that a Reformed scholastic/orthodox understanding of divine knowledge closely parallels Thomas Aquinas’s articulation of the subject within question 14 of his Summa Theologia. Specifically, it will be shown that men such as Stephen Charnock closely tied their understanding of divine omniscience with “Thomistic” claims such as actus purus and a belief in strong divine simplicity. For Charnock, it is because there exists perfect identity between the divine knower, the object of divine knowledge, and the act of divine knowing that God may be called omniscient. This, of course, is the same argument that Thomas utilizes when he calls God the First Truth. In other words, a Reformed scholastic doctrine of divine knowledge is unrecognizable apart from Thomistic insights. Evangelicals may bolster their understanding of divine omniscience, and their claims of God as Truth, if they are willing to incorporate such Thomistic insights into their doctrine of God. Otherwise, an evangelical doctrine of omniscience will be unrecognizable to the Great Tradition.