Student attitudes can have a positive or negative effect on learning. According to Duschl, Schweingruber, and Shouse, “[students’] goals for science learning, their beliefs about their ability to do science, and the value they assign to science learning are likely to influence their cognitive engagement in science tasks” (2007, p. 195). Therefore, the authors developed the Affective Elements of Science Learning (AESL) Questionnaire; an instrument that measures student attitudes to better understand them and design instruction to help improve them. In this article, they describe the various constructs that this questionnaire measures, the process they used to develop the instrument, and what they learned about student attitudes toward science along the way.