The purpose of this study is to examine the relationships between ninth grade students' metacognitive self-regulation skills and physics self-efficacy beliefs and their critical thinking. To this end, 162 students attending the ninth grade participated in the study. Critical thinking scale, metacognitive self-regulation scale and physics self-efficacy scale were used as data collection tools in the study. Data were analyzed by descriptive statistics, Pearson product moment correlation analysis, and stepwise multiple regression analysis. According to descriptive analysis results the students' critical thinking, metacognitive self-regulation and physics self-efficacy beliefs were high. Moreover, stepwise multiple regression analysis revealed that the students' metacognitive self-regulation and physics self-efficacy belief scores were significant predictors of their critical thinking scores, explaining 55% of the variance of critical thinking scores. In addition, it was also determined that the main variable that best explained critical thinking was metacognitive self-regulation, explaining 53% of variance.