The study explores the impacts and processes of traditional Confucianism on the green technology innovation behavior of organizations from the perspective of the informal system, using samples of Chinese A-share listed companies from 2003 to 2022. The findings indicate that Confucianism has a significant promotional effect on green technological innovation, which remains robust after using the cross-multiplier term between the number of regional Confucius temples and the mean ESG of firms as an instrumental variable to mitigate the endogeneity problem and a series of tests. According to mechanistic research, Confucianism works largely through two channels: reducing agency conflicts and raising environmental consciousness. Further investigation reveals that there is a substitution impact between Confucianism in the informal institution and environmental legislation in supporting green technology innovation in firms. To encourage green technological innovation in enterprises, it is critical to emphasize the integration of informal and formal systems, as well as to fully use traditional culture’s governance efficacy in supporting the enterprise green transformation.