<p>High-technology industry agglomeration and local government competition are important factors affecting regional green technology innovation, and clarifying the relationship between the three is of great practical significance for realizing regional green development. This paper examines the spatial spillover effects of high-tech industry agglomeration (HTIA) and local government competition on green technology innovation efficiency (GTIE) from a spatial perspective, taking the provincial panel data of China from 2010 to 2022 as a sample. We find that HTIA enhances local GTIE but generates negative spatial spillover effects. Government tax and public goods provision competition foster GTIE both locally and in neighboring provinces, while investment attraction competition has the opposite effect. Furthermore, the interactive effects show that government investment attraction amplifies the positive impact of HTIA on local GTIE and mitigates its negative spillover effect on neighboring provinces, whereas tax competition exhibits the opposite pattern. Public goods provision competition strengthens the positive impact of HTIA locally, but does not exhibit significant spillover effects. Regional analysis reveals substantial spatial heterogeneity in how HTIA and intergovernmental competition influence GTIE. A particularly striking divergence emerges in western China, where empirical findings markedly contrast with nationwide patterns, underscoring the importance of region-specific policymaking. These insights provide valuable policy implications for promoting regional green development.</p>