Universities have the opportunity to work on sustainable development challenges in a collective and creative way through their research and education. With interdisciplinary collaboration, the possibilities of developing new research ideas, methods and approaches are endless. However, to enhance the capability to become interdisciplinary collaborators and future problem-solvers, there is a need for opportunities to strengthen sustainability competences. This chapter focuses on how competence building in sustainable development can be incorporated in postgraduate training by sharing lessons from the Lund University Agenda 2030 Graduate School, created in 2018. The purpose of the school is to educate future leaders in sustainability and to support the university in becoming an international leader on sustainable development. Through research courses, idea exploration and cross-faculty collaboration, the doctoral students have been able to expand their competences beyond their scientific discipline. The Graduate School encompasses all eight faculties at the university, with a limited group of doctoral students at its core but with activities open to all postgraduate students at the university. The Graduate School has been running for five years, so it is now possible to draw some lessons. To what extent has the Graduate School delivered in terms of increasing competences on sustainability at Lund University? What has worked well? What have been the major obstacles and how have they been overcome? The chapter offers an overview of the Graduate School, its pedagogical approach, an assessment of its performance based on the initial vision to create the school, and a discussion of possible ways forward.