We interpret three key features within this definition that inform our research: (1) the intent to develop citizens prepared to take action; (2) the need for a holistic approach to ESD;and (3) the goal for education to be transformational. Developing students’ capacity to take action for a sustainable future calls for the identification of crucial competencies that enable students to think critically and creatively, make well-grounded, rational decisions, and act appropriately to address the problems that threaten their future (Van den Branden, 2015). UNESCO identifies key sustainability competencies that individuals will need for action in diverse and complex contexts, representing “an interplay of knowledge, capacities and skills, motives and affective dispositions” (UNESCO, 2017, p. 10). The competencies relate to