Abstract
In this study, it is aimed to examine the relationship between the psychological well-being and the metacognitive thinking and ruminative thoughts of university students. The study group consists of 175 students studying at Trakya University Faculty of Education Guidance and Psychological Counselling Program in the 2019-2020 academic year. The study was conducted by using the correlational model of quantitative research methods such as descriptive statistics, Independent Sample t-Test, One-Way Variance Analysis (ANOVA), and Pearson Correlation Coefficient techniques. The findings of the study show that the higher the metacognitive thinking level of the students, the lower their psychological well-being. In addition it is seen that students with high ruminative thinking levels also have high metacognitive thinking levels. Psychological well-being of the participant group does not change according to gender, grade level and whether or not to receive a psychological diagnosis. As a result it can be said that there is a significant and negative relationship between university students' negative metacognitive thinking, which is defined as "having some negative beliefs about thoughts that affect the evaluation of events", and their psychological well-being, and negative metacognitive thinking have a significant and positive relationship with ruminative thoughts.