The City of Niš (255.000 inhabitants) is the third largest city in Serbia and one of the oldest cities in the Balkans. Located in the region of South East Serbia, Niš hosts the administrative centre of the Nišava District of Serbia. It is considered an industrial and touristic centre of national importance. The City became a member of Energy Cities back in 2005, which positively influenced the way the local administration deals with sustainable energy development. In 2011, Niš joined the Covenant of Mayors initiative, becoming the first Serbian signatory and adopted its Sustainable Energy Action Plan in 2014. Niš’ dedication to the Covenant of Mayors initiative is proved by its efforts to mobilise other Serbian municipalities to join and by having set-up the Serbian Covenant of Mayors club. Niš is committed to find the best ways to involve of local stakeholders, citizens in particular in its energy transition, thanks to participatory decision making processes and the development of joint visions and roadmaps towards a greener future.