The aim of the present study is to improve the quality of students’ environmental literacy and sustainability education in chemistry teaching by combining the socio-scientific issue of life-cycle thinking with inquiry-based learning approaches. This case study presents results from an inquiry-based life-cycle thinking project: an interdisciplinary teaching model designed by chemistry teachers. The strength of the project is that upper-secondary students (N=105) are allowed to investigate the life cycle of an optional product based on their own interest. Studentcentred teaching methods are suggested to promote the students’ interest in studying. The research question was: How does an inquiry-based life-cycle thinking project in chemistry education affect students’ chemistry attitudes and environmental literacy? The research methods used included surveys and semi-structured interviews. The study shows that the project positively affected students’ attitudes towards chemistry learning: they valued the independent and collaborative learning setting. The changes in the students’ environmental literacy were evident in their new realisations: they emphasised the importance of environmental protection and recycling, but perceived that changing their own behaviour is still difficult. The inquiry-based teaching of life-cycle thinking can be seen as an effective approach to more motivating and sustainable chemistry education. Further research should address the kinds of knowledge outcomes that this type of inquiry-based life-cycle teaching creates in students. Furthermore, other useful approaches to teaching sustainable development in chemistry lessons should be shared.