This article argues that the controversy surrounding Theotokos at the Council of Ephesus was fundamentally Christological rather than Marian, while critically examining the council’s decision to canonize Marian terminology as a doctrinal boundary marker for Christology. While affirming the full deity and unity of Christ and recognizing the council’s historical intent to defend orthodoxy, the article contends that the terminology chosen at Ephesus carried long-term theological and devotional consequences far beyond its original context. From an evangelical and sola scripturaperspective, it argues that Scripture alone possesses final doctrinal authority and that post-apostolic terminology, however well intentioned, remains historically conditioned, fallible, and open to critique.