A science achievement model was separately investigated for students in low and high achieving schools (LAS and HAS) in Turkey. Then, gender differences based on variables that significantly contributed to each achievement model were investigated. The student-level variables that were under investigation for multiple regression analyses include attitudes toward science, epistemological beliefs, metacognition, views on science teaching, and socioeconomic status (SES). The science achievement scores of students on a nationwide exam were used to measure science achievement. Both for LAS and HAS, two schools were selected. Results were reported for 241 and 320 students in LAS and HAS, respectively. According to the results, self-concept in science, knowledge of cognition, SES, importance of science, gradual learning, and views on lab work significantly contributed to the science achievement model in LAS. On the other hand, self-concept in science, SES, gradual learning, studying, and learning science in school significantly contributed to the science achievement model in HAS. Results also revealed that girls outperformed boys on knowledge of cognition and importance of science in LAS. Moreover, girls scored higher than boys on gradual learning and studying in HAS. According to these findings, implications for science education were discussed.