Urbanization has caused multiple environmental grand challenges that impair urban sustainability. Urban vegetation (UV), a mainstream nature-based solution (NBS), can mitigate urban challenges through providing important ecosystem services (ESs). However, successful implementation of UV to provide ESs, is impaired due to insufficient knowledge of its effectiveness under different climatic and socio-economic conditions. Here, we quantify seven ESs provided by UV across 2,148 cities with ≥250,000 residents. We show that UV makes substantial contributions to outdoor recreation and stormwater regulation but is less effective in reducing air pollution, in most cities, regardless of the climatic and socio-economic context. The contributions of UV to carbon sequestration, coastal protection, shade provision, and land surface temperature reduction were generally smaller and varied substantially dependent on city climatic and human development index characteristics. Comprehensive assessments for urban NBS planning are essential to maximize ES efficacy for urban sustainability improvements and support human well-being.