["Business Strategy and the Environment, EarlyView. ", "\nABSTRACT\nThe supply chain is becoming less efficient because of various uncertainties. Because the majority of earlier studies have examined only individual uncertainty, determining the overall impact is challenging; earlier research did not examine how different uncertainties interact and share information. Therefore, in this paper, an analytical framework that integrates multiple dimensions of uncertainty is constructed, and the following hypothesis is proposed: Uncertainty negatively affects supply chain efficiency (SCE), and there is a synergistic inhibitory effect. Moreover, this effect is heterogeneous across different SCE quantiles. Methodologically, the joint impulse response function (jIRF), joint quantile impulse response function (jQIRF), and joint quantile forecast error variance decomposition (jQFEVD) were employed to effectively handle information overlap and capture asymmetric and time‐varying characteristics. The empirical results reveal that the individual and combined effects of these four types of uncertainties on SCE are significantly negative, and that the synergistic effect strengthens the inhibitory effect. The actual combined effect is indeed lower than the simple summation. In addition, the negative impact is significantly amplified at high quantile states, and the explanatory power of uncertainties on SCE shows a U‐shaped distribution.\n"]