The Leave no one behind (LNOB) approach is the central, transformative promise of the UN Agenda 2030 aimed at ensuring that no one is left behind in the pursuit of sustainable development. It requires local governments to pay special attention to the needs of the most disadvantaged and marginalised groups and to develop targeted interventions to address their specific needs and challenges. The economies of the South-East Europe (SEE) region have committed to implement the United Nations Sustainable Development Goals (SDGs), while the local governments took the commitment in the achievement of the 2030 Agenda, from the setting of goals and targets, to determining the means of implementation and using indicators to measure and monitor progress. The localising 2030 Agenda also put the territories and their peoples’ priorities, needs and resources at the centre of sustainable development. The achievement of the SDGs depends, more than ever, on the ability of local and regional governments to promote integrated, inclusive and sustainable territorial development.