The study investigates the impact of Content and Language Integrated Learning (CLIL) on the development of environmental knowledge and student engagement with key environmental issues compared to traditional teaching methods. A total of 100 middle school students were divided into two groups- an experimental group that received CLIL-based environmental instruction and a control group that received traditional instruction. Using pretest and posttest measurements, the study assessed changes in environmental knowledge and engagement with topics such as climate change, biodiversity and sustainability. The results showed that students in the CLIL group demonstrated significantly greater improvement in environmental knowledge, with an average posttest score of 81.9, compared to 66.2 for the traditional group. Additionally, qualitative observations indicated higher levels of student engagement in the CLIL group, as they actively participated in discussions and projects focused on environmental topics. The findings suggest that CLIL-based instruction is more effective than traditional methods in promoting both content knowledge and student engagement. The study highlights the potential of CLIL to enhance interdisciplinary learning by integrating language and environmental education, offering important educational implications for improving both academic outcomes and student involvement in global issues such as sustainability.