This study examines the impact of strategic alliances on corporate green innovation. We find that strategic alliances significantly promote corporate green innovation. Mechanism tests indicate that strategic alliances promote green innovation through channels of attracting market attention, alleviating agency problems, and stimulating collaborative innovation. Heterogeneity analysis demonstrates that the effects of strategic alliances are more pronounced for firms in areas with stringent environmental regulations and a favorable business environment, and firms facing intense product market competition. The findings provide new insights into the green transformation and upgrading of enterprises.