The COVID-19 pandemic has changed the face of cities around the world and has exposed underlying vulnerabilities of urban settings with implications for children's wellbeing. The authors conducted a rapid assessment for the UNICEF Evaluation Office to gauge the flexibility and agility of UNICEF's different urban programming approaches in response to the COVID-19 pandemic. The assessment focused on three countries—Brazil, India, and Spain—where UNICEF is actively engaged in urban programming using three different approaches: integrated, multi-sectoral, and Child-Friendly Cities Initiative. Drawing from the rapid assessment, the paper presents lessons from the three countries for future programming and emergency preparedness for the most vulnerable children in urban settings, particularly those in slums and informal settlements.