This document summarizes the Global Protocol for Community-Scale Greenhouse Gas Emission Inventories (GPC). The GPC provides a global standard for cities to consistently measure and report their greenhouse gas emissions. It establishes a framework that comprehensively accounts for all emission sources and provides flexibility for basic and more advanced reporting levels. The GPC was developed through a collaborative multi-year process involving over 30 organizations and input from over 200 stakeholders. It has been pilot tested by 35 cities and adopted by over 1,000 cities worldwide.