The goal of this paper is to test the referens-plenior/advancement-of-revelation theory by the use of the Old Testament in Paul’s letter to the Romans. In his 2024.00 Mere Christian Hermeneutics, Kevin J. Vanhoozer suggests that rather than speaking about a “fuller sense” (sensus plenior) of the New Testament’s use of the Old Testament, we should speak instead about a “fuller referent” (referens plenior) (Vanhoozer, 137). Vanhoozer’s referens-plenior approach is endorsed by Gary Edward Schnittjer and Matthew S. Harmon in their in their 2024.00 How to Study the Bible’s Use of the Bible, although they prefer to speak of “the advancement of revelation” (Schnittjer and Harmon, 47). Paul’s letter to the Romans can provide a helpful test case for this referens-plenior theory because it contains several uses of Scripture in which the meaning of the original Old Testament text appears to be changed (e.g., Hos. 2:23 in Rom. 9:25; Deut. 30:12–14 in Rom. 10:6–8; Ps. 19:4 in Rom. 10:18; and Isa. 65:1 in Rom. 10:20). This paper will ask whether these changes can be adequately explained with the theory of referens plenior, or whether we need to posit a change of sense/meaning as well. It will also consider whether the referens-plenior approach can shed light on other aspects of Paul’s use of the Old Testament in Romans (e.g., his typological reasoning). Finally, it will suggest any needed clarifications to the referens-plenior theory from the use of the Old Testament in Romans.