In this study, a path model was utilised to model the relationships among motivational beliefs, metacognitive strategy use, and effort regulation in science courses. There were 391 high-school students participating in the study. The Motivated Strategies for Learning Questionnaire was used to measure students' motivational beliefs, metacognitive strategy use, and effort regulation. Results showed that intrinsic goal orientation, beliefs about value of a task, control of learning beliefs, and self-efficacy for learning and performance were predictors of students' metacognitive strategy use. Effect of motivational beliefs on effort regulation was mediated through metacognitive strategy use. In addition, the path model revealed interrelationships among motivational beliefs. It was concluded that students should have motivation to use metacognitive strategies and engage in a task.