The present study examines and compares the interpretive approaches of Shia and Sunni schools regarding authentic and inauthentic (interpolated) narrations concerning the story of Prophet Lot (peace be upon him). The stories of the prophets, particularly the narrative of Lot, have always attracted the attention of exegetes from both traditions; however, inauthentic narrations—including Isrāʾīliyyāt (Judeo-Christian traditions) and weak reports—have found their way into commentaries, posing challenges to the understanding of the text and the authentic narrative. Employing an analytical-comparative method, this research reevaluates and purifies the story of Lot in early commentaries of both schools. Alongside clarifying the criteria for distinguishing authentic from inauthentic narrations, it identifies the most significant instances of spurious traditions and presents a sound interpretation. The findings indicate that while the two traditions share common ground in the general outlines of the story, there are substantive differences in narrative details. Recognizing inauthentic narrations contributes to correcting the historical-doctrinal understanding of Qur'anic stories and to deriving educational and moral lessons.Keywords: Authentic Interpretation, Inauthentic (Interpolated) Interpretation, The Holy Quran, Qur'anic Stories, Prophet Lot (pbuh), Critique of Narrations, Shia and Sunni Schools, Sodomy