The share of older people in OECD cities is rising fast, and many large cities continue to grow and attract young people. Without age-inclusive policies, cities risk significant social and economic consequences, ranging from poorer health outcomes and higher isolation to workforce loss, increased public spending, and brain drain. The Cities for All Ages report explores how local and national governments can address these challenges and make cities work for all generations. It highlights strategies such as adapting urban design and land use planning for more accessible cities, providing age-friendly housing, and engaging both young and older people in labour and consumer markets. To drive progress, the report offers a checklist of nine policy actions across three key areas - strategy setting, resource development and stakeholder co-ordination - to help local and national governments shape cities for all ages.