The Temple of Bacchus at Baalbek, Lebanon, as one of the most prominent preserved examples of Roman religious architecture in the Eastern Mediterranean, provides a unique opportunity to study these interactions. This research aims to analyze the architectural structure of the Adyton in the Temple of Bacchus and examine the influence of local and regional elements on the formation of its spatial form and decorative program. the main research questions are: First, what common and distinctive features does the architectural structure of the Adyton possess compared to the inner sanctuaries of Greek, Roman, and Levantine temples? Second, how have local traditions and regional cultural dynamics influenced the spatial structure and decorative program of the Temple of Bacchus's Adyton? the methodology of this research is interdisciplinary, drawing upon classical literary sources, archaeological evidence, and comparative architectural analysis. The findings demonstrate that the Adyton of the Temple of Bacchus, unlike Greek and Roman examples, was constructed as an elevated, roofed structure adorned with Dionysian reliefs and eastern symbols, functioning as a shrine and sanctuary. Comparative study with contemporary temples such as Niha, Qasr al-Banat, Palmyra, and Hauran places the Adyton of the Temple of Bacchus within the Lebanese-Heliopolitan subtype, highlighting features such as staircases, gabled roofs, temple-like facades, and spatial introversion. the research results indicate that the Adyton of the Temple of Bacchus, rather than reflecting Greco-Roman style, demonstrates the resilience and continuity of Middle Eastern local traditions and represents a manifestation of cultural syncretism in the eastern provinces of the Roman Empire, where indigenous elements, despite the apparent dominance of classical forms, preserved the essential core of architectural identity.