It is emphasized in several studies that both domain specific factors and cultural values and beliefs could have an effect on students' metacognitive self-regulation and motivational beliefs. The aim of this study was to investigate the effect of motivational beliefs on Turkish students' metacognitive self-regulation in physics courses. Therefore, the contribution of the students' learning goal, performance goal, and self-efficacy beliefs in physics on their metacognitive self-regulation in physics was investigated. 187 Turkish preservice teachers taking introductory physics courses participated in this study. In order to assess students' use of metacognitive strategy in physics, metacognitive self-regulation subscale of Motivated Strategies for Learning Questionnaire was used. The students were requested to consider the strategies they used in relation to the physics course they took. The subscales of the Achievement Motivation Questionnaire were used to assess students' learning goals, performance goals, and the self-efficacy in physics course. The results of the study were evaluated by using SPSS with the help of descriptive statistics and stepwise multiple regression analysis. The results showed that students' metacognitive self-regulation in physics scores was high and besides; their scores for learning goals were higher than those for performance goals. Moreover, stepwise multiple regression analysis revealed that learning goals and physics self-efficacy were significant predictors of students' metacognitive self-regulation in physics scores explaining 33% of the variance.