Every sphere of life has been revolutionised by science. Thus, science understanding is an increasingly precious resource throughout the world. Despite the widely recognised need for better science education, the percentage of school students studying science is particularly low, and the numbers of students pursuing science continue to decline internationally. This study establishes a new measure to investigate students' science self-concepts, motivation, and aspirations. The instrument shows sound psychometric properties in investigating secondary students' science self-concepts in different disciplines of science. Though available data show that students' science self-concepts are domain specific, it could not be shown that motivation and aspirations are.