Cooling is one of the biggest untapped opportunities to deliver climate, health, and development gains together. While the sector already contributes seven per cent of global greenhouse gas emissions, and could double that share by 2050, over one billion people still lack access to life-saving cooling for health, food security, and medicine. This guide supports governments in confronting this challenge by integrating sustainable cooling into their Nationally Determined Contributions (NDCs). The NDC Cooling Guidelines offer a six-stage, step-by-step framework, supported by country case studies, to help policymakers assess hydrofluorocarbon and energy-related emissions, set sector-specific targets, and develop fully costed National Cooling Action Plans (NCAPs). The Guidelines emphasize Minimum Energy Performance Standards (MEPS), Kigali-compliant refrigerant phase-down, passive and nature-based solutions, as well as climate-responsive urban planning. These actions are underpinned by cross-ministerial coordination, a robust Measurement, Reporting, and Verification (MRV) system to track progress, and a strong focus on expanding equitable access. Together, they enable countries to integrate cooling measures into both adaptation and mitigation pathways. The NDC Cooling Guidelines were developed collaboratively by the UNEP Cool Coalition NDC Working Group, with contributions from the American University in Cairo; Climate and Clean Air Coalition (CCAC); Clean Cooling Collaborative (CCC); Collaborative Labeling and Appliance Standards Program (CLASP); Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) Proklima; the Ozone Secretariat; Sustainable Energy for All (SEforALL); United Nations Development Programme (UNDP); UNEP Copenhagen Climate Centre (UNEP-CCC); and UNEP United for Efficiency (U4E).