The study aims to develop a scale to assess high school students' attitudes toward sustainable development. For this purpose, 90 Likert-type scale items pertaining to attitudes were initially developed based on existing literature. Further consultations with experts led to a reduction of the item count to 60, followed by a further reduction to 40 items. The scale was administered to 509 students enrolled in an Anatolian high school, a science high school, and an Anatolian religious vocational high school in Akçaabat. The data gathered were analyzed using the SPSS 18.0 statistics package. An item analysis, comprising the item-total correlation test, was performed on the scale, which was followed by a reliability analysis that focused on the Cronbach's alpha internal consistency factor. Furthermore, factor analysis was performed to determine the validity of the scale. The factor analysis led to the development of a two-factor scale composed of a total of 14 items. The Cronbach's alpha internal consistency factor of the scale is 0.811. The scale was deemed appropriate for assessing the attitudes of high school students with regards to sustainable development.