The study of Qurʾanic exegesis systematically deals with the understanding of the Qurʾan. It interprets the Qurʾan and works out the text hermeneutically. Depending on the systematic approach, exegesis can pursue different goals. One of these goals is to present the historical context to overcome the temporal distance that readers of the Qurʾan have, which allows the exegete to recognize the Qurʾanic message and, among other things, reinterpret it for their own time. Exegetical activity can also represent a reconstruction of the revelation event. In this context, especially exegetical traditions play a role. Early exegesis relies on exegetical traditions that provide insight into the meaning of Qurʾanic revelation. Exegetical traditions include information on the occasion of revelation (sabab an-nuzūl), interpretations of specific individuals to a Qurʾanic passage, reactions of the first listeners, their worldview, religious convictions, practices, and environment of the Qurʾan and the Umwelt of the first recipients. Therefore, the transmitted material is not uniform in type. In addition to their interpretations of the companions of the Prophet or scholars of the next generation, some traditions contain information on the occasion of the revelation of certain Qurʾanic passages or surahs. Another category of traditions is those that contain biblical information. Muslim commentators have relied on the isrāʾīliyyāt material, which deals with the shared history of Jews and Christians, to understand Qur'anic content. This paper discusses the Christian influence in Muslim tafsīr literature, focusing on the various terminologies used to refer to Christians. While the clarification of terminologies of Christian groups does not provide sufficient insight into possible Christian sources of Muslim exegetes, it offers a general overview of their usage. This understanding is essential to comprehend the perception and knowledge of Muslim exegetes regarding Oriental Christians and their classification referring to Christian groups. First, the article presents the terms used in exegetical works for Christian groups, followed by specific group designations by Muqātil Ibn Sulaymān and Ibn Jarīr al-Ṭabarī to gain an overview of the terminologies used. Muqātil Ibn Sulaymāns and Tabari's commentaries show that they were aware of the heterogeneity of various Christian groups, with the Syrian Christians forming the main axis of the groups he mentions. However, their explanations of Syrian Christian groups do not match what we know about them, and the sources they used to classify Christian groups are unclear. Moreover, Muqātil's and Tabari's interest in providing information about Christian groups is likely to place theological criticisms of Christianity in the Qurʾan in their proper context rather than to give an authentic perspective on Christianity.