Purpose: This study aimed to develop an attitude scale to find out middle school students' (grades 5 through 8) attitudes towards science and to investigate the effects of grade level on students' attitudes towards science. Research Method: Cross-sectional survey method was used in this study. The attitude towards the science scale developed by the researchers was applied to a sample of 691 middle school students. Fifth, sixth, seventh, and eighth-grade students' level of attitudes towards science were determined and compared through this scale. Findings: The data, which were collected in this study, were analyzed using SPSS 22.0 package program and analyzed by Exploratory Factor Analysis (EFA) to establish the construct validity of the scale. The data were analyzed by confirmatory factor analysis to show the validity of the four-factor structure that was generated by EFA, and it was seen that this four-factor structure was at an acceptable level. Implications for Research and Practice: The findings of this study showed that there was not any significant difference between 5th, 6th, 7th and 8th-grade students' attitudes towards science scores. Cross-sectional studies with various scales may be conducted for different grade levels and different disciplines in future studies. Attitude studies of cross -age characteristics and various scale studies may be carried out to find out the relationship between different age groups and attitude scores towards science.