This paper describes an assignment given to fourth-year Industrial Engineering and Management (IEM) students in a Project-Based Learning (PBL) developed in the context of university-business partnerships. The aim of this assignment was students assess sustainability business effectiveness in an industrial context. To achieve this, they must use an indicator that was explained in the context of Lean-Green synergy, a content lectured in the course Production Systems Organization II (PSOII) of the fourth year IEM program of the School of Engineering at University of Minho. This course is one of the five courses which contents must be integrated into the Integrated Project of Industrial Engineering and Management II course, under PBL. Students worked in teams of 6–10 students and developed their projects in companies. The cohort of 2020–21 involved 12 teams in a total of 100 students. In each company, teams had a supervisor that supported and supervised their work. Teams had to organize themselves to attend lectures in university and visit the companies according to companies’ availability, which was difficult by the pandemic situation. The project developed under PBL is related to the analysis and proposals improvements for companies’ production system applying the knowledge and contents learned in courses of fourth or previous years. Taking into account the results obtained in the indicator used, the teams had to propose some environmental and operational improvement actions to increase it. The teams’ main findings, the sustainability learning process, and outcomes are discussed in the paper.