This study explores engineering design students' perceptions of their agency for sustainability in a Danish problem- and project-based learning (PBL) context. A conceptual framework is proposed with three dimensions: personal, action, and contextual. Q methodology was adopted to investigate the subjective views of 24 first-year undergraduate students in a Sustainable Design program regarding the most important contributors in their development of agency for sustainability. The Q factor analysis identified three prevailing opinions, which emphasized: 1) The professional role of engineering designers to act for the United Nations' Sustainable Development Goals (SDGs); 2) The role of the formal curriculum in building the foundations to act for the SDGs; and 3) Collaboration within and beyond the university. These results indicate the complexity of student agency and highlight PBL's effectiveness for supporting students' learning for sustainability across all three dimensions of student agency. The results also suggest that institutions and educators should design more formal and informal sustainability-related activities with clear structures and well-defined regulations and strategies for sustainability.