The Xiaotazigou gold deposit is located in the eastern section of the Chifeng–Chaoyang gold metallogenic belt on the northern margin of the North China Craton. In this study, rare earth and trace element compositions of ores and host rocks, together with sulfur isotope data, were applied to constrain the geochemical characteristics of ore-forming fluids and the sources of ore-forming materials. The results show that the ores are enriched in light rare earth elements (LREE) and display negative E