Open government data (OGD) is pivotal for urban sustainable development, and this study is the first to explore the relationship between OGD and urban green economic efficiency (GEE). Analyzing data from Chinese cities spanning 2008 to 2021 and employing the staggered difference-in-differences approach, the study makes the following findings: First, OGD significantly enhances GEE. Second, the theoretical mechanisms are verified from the perspectives of market efficiency and government governance. OGD fosters green innovation and bolsters government environmental governance capabilities, thereby increasing GEE. Third, OGD exhibits a positive spillover influence on GEE, with the optimal spillover distance being 250 km. Lastly, the influence of OGD on GEE is heterogeneous. This study enriches the existing literature on the effects of digital government initiatives on GEE and offers essential insights for activating the value of data resources and fostering sustainable development.