NetZeroCities, a project within the Horizon 2020 Research and Innovation Programme supporting the European Union’s Green Deal, aims to assist cities in overcoming structural, institutional, and cultural barriers to achieve climate neutrality by 2030. Aligned with the EU’s Mission of “100 Climate-Neutral and Smart Cities by 2030,” the project functions as a service-oriented platform, offering support and solutions to European cities. Through an online portal, cities can access tools, resources, and expertise, tailored to their needs. NetZeroCities also conducts Pilots and a Twinning program to facilitate peer-learning and accelerate progress towards climate neutrality at the city scale.