This paper describes the implementation and evaluation of the flipped classroom approach in a sustainability course for undergraduate engineering students. Using a mixed methods approach, the evaluation focused on student engagement, performance as well as students’ attitudes and beliefs about the flipped classroom. A novel aspect of this work compared to previous studies on the flipped classroom is the tracking of student attitudes and engagement during the course. The results indicate that while student attitudes grew more neutral during the middle of the course, student engagement as well as performance on the final written exam increased significantly compared to previous years. Pedagogical implications for instructors wanting to implement the flipped classroom approach are briefly discussed.