Background: This study uses problem-based learning (PBL) to ensure that students comprehend the significance of green chemistry better by experiencing the stages of identifying the problem, developing hypotheses, and providing solutions within the problem-solving process. Purpose: The aim of this study is to research the effect of PBL implemented in cation analysis experiments in an analytical chemistry laboratory course on students' level of understanding of the subject of "Green Chemistry and Sustainability." The study group: The study group consists of second-grade students who participated in an Analytical Chemistry Laboratory within the General Chemistry III course in the Department of Science Education of the Faculty of Education of a state university in Turkey (N = 63). Design and methods: Quasi-experimental design was used in this research. Students were randomly divided into two groups, an experimental group (N = 31) and a control group (N = 32). Laboratory experiments in which qualitative and quantitative cation group analyses were conducted were carried out in the experimental group with PBL that involved five different scenarios inspired by daily life. In the control group, experiments were performed as closed-ended experiments. The "Green Chemistry and Sustainability Test" (GCST) and semi-structured interviews were used as data collection tools. The independent sample "t"-test was used in determining whether there was a significant difference between groups by GCST, reviewing pre-test--post-test scores for the control and experimental groups, and semi-structured interviews were analyzed by content analysis. Results: The results showed that there was a significant difference in favor of the experimental group in GCST post-test scores ("t" = 10.554, p < 0.05). Considering students' opinions, there were positive statements, such as that they had taken an active role and had their interest aroused interest since problems in the experiments were related to daily life. Conclusion: PBL enhanced students' level of understanding of green chemistry and sustainability subjects and helped them obtain a different perspective in terms of environmental awareness.