CITY-MOVE adapts and implements the WHO Global Action Plan on Physical Activity (GAPPA) in six cities across three continents and develops a cross-contextual evaluation framework for transferability and scalability. Physical activity is a key behavior to reduce the NCD burden, including protecting against cancers and type 2 diabetes. There are many evidence-based interventions for cities to promote physical activity, yet they remain under-implemented, with a whole-of-system approach particularly lacking, and often fail to target the least active or vulnerable groups. Knowledge gaps are: a) how to adapt, b) successfully implement, and c) evaluate interventions, and d) how to transfer lessons to other interventions, target groups and contexts. In partnership with the cities, we identified interventions targeting individuals across the life course, particularly vulnerable and least active groups, aligned with the GAPPA domains of active people, societies, environments and systems. CITY-MOVE will: 1) Develop a city-GAPPA Theory of Change and operationalise assessment measures; 2) Adapt city-GAPPA to six cities, engaging stakeholders in each context; 3) Support cities in successful implementation through action research in living labs; 4) Assess reach, adoption, feasibility, fidelity, and sustainability of selected interventions in each city; 5) Improve the development and utilisation of routinely collected data to support successful implementation; 6) Generate cross-contextual evidence on implementation, evaluation and scalability through multi-criteria decision assessment for 12 interventions in six cities; and 7) Generate global capacity through regional Communities of Practice. CITY-MOVE results lead to increased physical activity by target populations, contributing to reduced premature NCD mortality, and to adaptable solutions ready for take-up by implementers.