How does the deployment and withdrawal of UN peacekeepers affect local economic development in civil war countries? This study provides a large-N subnational analysis across UN peacekeeping operations that assesses their impact on the local economy both during deployment and after their withdrawal. We expect a positive association between UN peacekeeping and economic development. Besides providing a sizeable cash injection into the economy, peacekeepers can safeguard both the resumption of everyday economic exchanges at the grassroots level and the influx of aid and development projects. To test this, we combine subnational data on peacekeeping deployments with high-resolution data on nightlight emissions. Results from two-way fixed effects models, using matching, show that a more sizable peacekeeping presence can help boost economic activity in their area of operation. Importantly, we identify a slow but positive economic development in areas of deployment after peacekeepers withdraw, which is confirmed in a DiD estimation approach.