Abstract Atmospheric emissions pose significant challenges to achieving the Sustainable Development Goals (SDGs). As key sources of emissions, cities are also critical actors in driving sustainable transitions. Their performance on emission-related SDG indicators is shaped not only by local factors but also by inter-city interactions. However, the spatial and temporal heterogeneity of these interactions remain poorly understood. Here, we investigate inter-city SDG interactions across 4,116 cities worldwide from 2010 to 2020, and simulate SDG performance under five interaction scenarios, including isolated and collaborative conditions. Results reveal that a 10% improvement in SDG 11.6 (particulate matter), SDG 12.4 (gaseous pollutants), and SDG 13.2 (greenhouse gases) in other cities can boost the focal city’s performance by 0.450%, 0.390%, and 0.200%, respectively. Most cities (93.51%) are influenced by other cities. Inter-city coordination can improve SDG performance by 10.81% compared to isolated efforts. These findings highlight the importance of coordinated strategies to enhance urban sustainability. Funding This research is supported by the Hong Kong Research Grants Council’s collaborative research funds (project no. C6032-21G to M.L.), general research fund (project no. 16300424 & 16215820 to M.L.), theme-based research scheme (project no. T22-501/23 R, T22-607/24-N to M.L.), NSFC/RGC Collaborative Fund (project no. CRS_PolyU503/23 to M.L.), “1 + 1 + 1”Joint Funding Program (project no. 2025A0505000018 to M.L.), National Science Foundation (2118329 to J.L.), Michigan AgBioResearch (to J.L.), and the Excellent Young Scientists Fund from the National Natural Science Foundation of China (Grant No. 42422105 to Z.X.). All co-authors at HKUST acknowledge the support by the Otto Poon Center for Climate Resilience and Sustainability at HKUST. This research has received funding from Global STEM Professorship (to Q.W), Hong Kong SAR Government (P0039329 to Q.W), and Hong Kong Polytechnic University (P0046482 and P0038446 to Q.W). This work is part of the United Nations Educational Scientific and Cultural Organization