ABSTRACT Based on the Chinese Annual Survey of Industrial Firms (CASIF) database, this paper constructs a PSM-DID model to analyse the impact of cross-border mergers and acquisitions (M&As) on the export green-technological sophistication of Chinese industrial firms. The results show that cross-border M&As can effectively promote the export green-technological sophistication of acquired firms. The promoting effect of M&As increases gradually over time. Further, the heterogeneity results demonstrate that the promoting effect is more significant in private firms, partially acquired firms, firms in pollution-intensive industries and eastern areas. Finally, cross-border M&As can improve the export green-technological sophistication through two channels: improving green innovation capabilities and introducing pollution control equipment. Our results are significant for developing countries’ foreign investment guidance policies and firms’ green transformation.