The purpose of this study is to examine students’ attitudes towards science with respect to grade level and gender in middle schools with different science achievement levels. For that purpose, two middle schools having low achievement level and one middle school having high achievement level were selected according to the information given by officials working in National Education Directorate of Kastamonu province about middle schools’ achievement levels in Kastamonu. Study sample consisted of 282 students at different grade levels attending to two low achieving schools and 302 students attending to the high achieving school. Attitudes towards Science Scale was used as the data collection instrument. Results of factor analyses showed four factors under this instrument: learning science in school, science outside school, self concept in science, and importance of science. Study results showed that grade level had a significant effect on only science outside school subscale of Attitudes towards Science Scale both in low and high achieving schools. Furthermore, for all grade levels no significant effect of gender on any subscales of Attitudes towards Science Scale was observed in low achieving schools. On the other hand, it was found that gender had a significant effect on different subscales of Attitudes towards Science Scale in 5th, 6th and 7th grades in high achieving schools. Recommendations were given about what cautions can be taken for the development of attitudes towards science among students in both school types and how to close gender-based attitude gap which was found in favor of girls only in the high achieving school.