This OECD National Urban Policy Review of Colombia provides a comprehensive assessment of the country’s national urban policy ‘the System of Cities’ and of different sectoral policies that affect urban life: transport, housing, land use, and digitalisation. Colombia has entered the 2020s facing five intertwined crises: the COVID-19 pandemic, rising levels of poverty and inequality, a wave of mass international migration, the peace process consolidation, and the climate emergency. As the country seeks an answer to all those challenges, Colombia’s social and economic prosperity and environmental sustainability will be more tightly linked to the functioning of its cities and its urban governance system. This OECD review makes the case for an integrated, placed-based and inclusive urban development model and urban agenda that seize immediate opportunities that arise in fiscal, economic and sectorial policies, and protect hard-won gains from years of experience of urban policy implementation in the country. Designing a new national urban policy for Colombia – Ciudades 4.0 – demands a critical rethinking of whether urban areas are meeting the needs of all Colombians, and how different urban-related policies could help transform them for the better.