AbstractThis paper examines the strategic relations between emission taxes and firms' managerial delegation contracts, which include incentives based on relative profit performance (RPP) and environmental performance (EP). We demonstrate that under quantity (price) competition, the government imposes higher (lower) emission taxes, while the firm owner sets lower (higher) EP incentives and negative (positive) RPP incentives, which leads to lower (higher) welfare. We also explore an endogenous competition mode game and find that quantity (price) competition emerges when both consumers' green willingness‐to‐pay (WTP) and product differentiation are low (high). Our findings suggest that public education on greenness is crucial for enhancing EP incentives in the design of managerial delegation contracts, while intense product market competition may be detrimental to consumers and society, especially when consumers' green WTP is low.