Abstract
Background Green chemistry is increasingly promoted as a way to connect school science to real-world sustainability challenges. Yet in Kazakhstan, environmental and sustainability topics remain minimally represented in secondary chemistry education.Purpose This study investigated the impact of an elective green chemistry course that integrated systems thinking on students’ conceptual understanding, environmental awareness, and reasoning skills.Sample The course was implemented with 120 tenth-grade students in a public secondary school in Kyzylorda, Kazakhstan.Design and methods A convergent mixed-methods approach was employed. Pre- and post-course surveys measured changes in students’ knowledge and attitudes, while interviews, classroom observations, and student project evaluations provided qualitative insights. Project assessments were conducted by three independent raters, and inter-rater agreement was substantial.Results Findings indicated clear improvements in students’ understanding of green chemistry concepts, their ability to analyze chemical decisions in broader ecological and ethical contexts, and their use of systems thinking tools such as causal mapping and trade-off analysis. Students demonstrated increased motivation and real-world awareness, while teachers reported deeper engagement and more meaningful classroom discussions.Conclusion The study shows that integrating green chemistry and systems thinking within an elective course can meaningfully enhance sustainability competencies in secondary education, even within a centralized curriculum. The approach offers a practical, scalable model for curriculum innovation in similar educational contexts.