This study investigates the effects of tax incentives on export product quality. Using a staggered value‐added tax reform in China as exogenous shocks, our difference‐in‐differences estimation shows that tax cuts causally reduce product quality at the firm‐level (product‐level) by 5.3% (8.6%). A plausible mechanism appears to be the output and export expansion, which crowd out human capital and thus undermine quality. The results are more pronounced for non‐state‐owned firms, firms under high tax reinforcement effort, and firms subjecting to high financial constraints. This study provides clear policy implications by shedding light on the unintended consequences of tax incentives on export product quality.