It is vital that subjects such as the circular economy, sustainable design, green computing or environmental engineering be included in the engineering curriculum. Education for sustainable development will enable engineers to develop sustainable products and provide sustainable services, thereby leading to a beneficial result for society and making an indispensable contribution to the Sustainable Development Goals achievement. As the last stage for students in academia, Degree Theses (Bachelor’s and Master’s) provide a good tool for reviewing the sustainability competencies developed during the degree, as well as being an opportunity for applying these competencies in a holistic way. In their Degree Theses, students should be able to demonstrate that they are aware of the need to introduce and assess sustainability in their future engineering projects. This paper presents a guide aimed at helping engineering students to design and develop sustainable projects, and analyzes the first results of its use in two schools of the Universitat Politècnica de Catalunya—BarcelonaTech. The proposal is based on a tool referred to as “the Sustainability Matrix”, in which cells contain questions that engineering students should take into account when undertaking their Degree Theses. The questions are related to the project development, the project exploitation and the possible risks involved, three aspects in accordance with the sustainability dimensions (economic, environmental and social). The Sustainability Matrix helps students to develop sustainable projects when they graduate, and teachers to assess how sustainability is incorporated across the curriculum in the subjects they teach and in the students’ Degree Theses.