The aim of this short paper is quite narrow: to propose an alternate solution to the source behind the citation of Zechariah 9.9 in Matthew 21.5. Scholars have already proposed various solutions: the Old Greek, Masoretic Text, a combination of both Greek and Hebrew texts, and even the possibility of a Greek recension distinct from the Old Greek. It is quite evident the citation does not entirely conform with extant Hebrew versions or the Old Greek version. Yet, many scholars simply note various agreements with the Old Greek and the Masoretic Text without arguing for a specific Vorlage.Maarten Menken proposes a Vorlage rooted in a revised Septuagint version, though he doesn’t argue for a specific version. Of all these possibilities that the paper will expose, Menken’s solution of a revised Old Greek version best explains the complexity of the latter half of the citation However, whereas Menken’s proposal ceases with “a revised LXX”, this essay specifically argues for a particular Old Greek revision from which Matthew likely drew—the “proto-Theodotion” Greek revision, whose readings have made their way into several OT citations within the NT. To be sure, due to scant extant material, this study is not conclusive; the proposal put forth here is merely a preliminary solution. Nonetheless, the thesis provides the best explanation to the Vorlage of Matthew 21:5 and raises broader questions of the use of “proto-Theodotion” within the NT.