This study examined the differences in the level of 7th-grade Turkish students' cognitive and metacognitive strategy use (rehearsal, elaboration, organization, critical thinking, and metacognitive self-regulation) in science and investigated the contribution of cognitive and metacognitive strategy use to students' science achievement. The present study also explored the relationships between students' background characteristics (gender, prior knowledge, socioeconomic status) and their cognitive and metacognitive strategy use and science achievement. The statistical analyses revealed significant differences in the level of students' cognitive and metacognitive strategy use scores. Besides, elaboration, organization, and metacognitive self-regulation strategy use were found to make a significant contribution to students' science achievement. Moreover, prior knowledge, parents' educational level, number of reading materials at home, frequency of buying a daily newspaper, presence of a separate study room, and presence of a computer with internet connection at home were significantly associated with cognitive and metacognitive strategy use and science achievement. (Contains 7 tables.)