In order for ESD-related interventions to gain real traction, a concerted sector-wide effort is needed. It is not enough to adjust policy, or include reference to sustainability in curricula if, for example, examination systems remain grounded in content knowledge, or adequate teacher professional development is not provided to facilitate the shift. The Tongan example has good potential from the perspective of system-wide ESD integration because of the relative coherence of a number of its policy initiatives around themes of culture and sustainability.