Oriental Sweetgum (Liquidambar orientalis) is a threatened tree species restricted to Rhodes Island (Greece) and southern Anatolia (Turkey), best known for its rare riparian forests. These small patches of forests are severely fragmented and scattered, and are rarely found in southwestern Turkey. Based on field sampling and data compilation, we performed an assessment of the herpetofauna in these forests in southwestern Turkey during the spring of 2019 and 2021. Sampling was carried out using a line-transect method in 13 forests with various habitats, resulting in data at the community and population levels. Sixteen families, including 26 amphibian and reptile species (four anurans, four turtles, nine lizards, and nine snakes), were recorded from these unique forests, based on 1440 individuals. Twenty-two species were recorded for the first time from these forests; in addition, Emys orbicularis and Elaphe sauromates were recorded for the first time from the region. Richness in the forest patches, habitat use by the recorded species, and interspecific interactions are discussed to explain the conspicuous patterns observed in the species distributions. The unique distribution pattern of Phoenicolacerta laevis among the existing forest patches represents the most prominent finding, with implications for a recent introduction. The fossorial species Xerotyphlops vermicularis, Blanus strauchi, and Eryx jaculus are unlikely to occur in the Oriental Sweetgum forest due to annual flooding. The data obtained during this study will be transferred to the Oriental Sweetgum forest conservation action plan (2019–2024) as part of the biodiversity monitoring tools for use in the long-term conservation of these forests.