<p>Drawing on contingency theory, this study empirically investigates how psychological safety enhances improvement capability (including its maintenance and improvement dimensions) across different levels of manufacturing complexity (product complexity and process complexity). Using a cross-sectional dataset of 330 manufacturing plants from the 4th round of the High-Performance Manufacturing Project, we tested the proposed relationships through moderation analysis. The results indicate that psychological safety has a strong positive impact on improvement capability, particularly in the improvement dimension. Unexpectedly, the findings do not support the moderating effect of manufacturing complexity on the relationship between psychological safety and improvement capability. However, a post hoc analysis reveals that product complexity negatively moderates the relationship between psychological safety and the improvement dimension, suggesting that the effect of psychological safety on the improvement dimension is less salient under conditions of high product complexity. Our findings contribute to continuous improvement and psychological safety literature in two ways: (1) by integrating continuous improvement literature and positive organizational scholarship to empirically examine the facilitating role of psychological safety on improvement capability, and (2) by empirically investigating the efficacious of psychological safety in facilitating improvement capability across different levels of manufacturing complexity.</p>