The development of valid and reliable instruments for attitudes' measurement has been proven crucial for the quality of research. This study is dealing with the development and validation of an attitude toward chemistry instrument. By using this instrument, 11th grade Greek students' attitudes regarding the difficulty, the interest, the usefulness of chemistry course, and the importance of chemistry were investigated. Gender and study specialization differences in students' attitudes toward chemistry were examined for this population. Report card grades for the chemistry course were used to measure students' achievement in chemistry and its correlation with students' attitudes toward chemistry was explored.