The continuous development of industry and industry drives people to seek new resources, and for this purpose, the usage areas of Rare Earth Elements (REE), whose usage areas are increasing day by day, are increasing rapidly. Increasing concentrations of REEs as a result of increased use create pollution in the environment and harm living organisms. This pollution interacts with increasing temperature and causes more negative synergistic effects of the pollutant in the environment and the living body. In this study, sublethal concentration values were determined by literature review and the concentration value was determined as 125 mg/L. It is aimed to investigate some oxidative stress and antioxidant responses of Terbium, Lanthanum, Gadolinium and Praseodymium REEs in Dreissena polymorpha at 125 mg/L concentration at 3 different temperatures (16, 18, 20 0C) with biomarkers. For this purpose, a 24-hour and 96-hour trial design was created and 7 D. polymorpha were used in each trial group, and the application experiments were carried out in 3 repetitions. The samples, whose trial phase was finished, were kept at -80 degrees until analysis. In this study, Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) enzyme activities and gulutathion (GSH) and Thiobarbituric acid (TBARS) level biomarker responses were determined with ELISA test microplate reader. CAYMAN brand SOD (Catalog No 706002), CAT Catalog No 707002) and GPx (Catalog No 703102), GSH (Catalog No 703002) and TBARS (Catalog No 10009055) were used in the study. According to the study data, statistically significant decreases were observed in SOD and CAT activities in the oxidative stress responses of REEs on D. polymorpha with increasing temperature, while there was no significant change in GPx activities. It was determined that there were increases in TBARS levels and decreases in GSH levels.