Stakeholder report: A multi-method study across Belgium, Cyprus, Italy, Romania, and Turkey engaged 274 participants (36 expert interviews + 238 student surveys) to examine how sustainability is understood and implemented in European HEIs, covering curriculum, pedagogy, governance, and student engagement. Findings show strong institutional commitment and visible campus practices, but limited curricular integration of sustainability and marked disciplinary differences—especially higher engagement in Business vs. Engineering—highlighting a perception-implementation gap. The report offers strategic recommendations and a four-phase roadmap (foundation, integration, expansion, innovation) to embed sustainability systemically through leadership, faculty development, partnerships, and robust impact measurement.