<p>Maintaining investment efficiency has become increasingly important for firms in an environment characterized by elevated uncertainty. This study examines the relationship between firm-level uncertainty and investment inefficiency of Chinese listed firms, highlighting the crucial role of corporate internal control in preserving investment efficiency. Using newly constructed measures of firm-level uncertainty and an unbalanced quarterly firm-level panel data covering the period from 2009 to 2022, the results show that heightened firm-level uncertainty worsens investment inefficiency. However, the adverse effect is mitigated for firms with a robust internal control mechanism. Mechanism analysis shows that internal control offsets the effect of uncertainty on investment inefficiency by reducing corporate underinvestment. Moreover, analysis using disaggregated internal control indicators suggests that strategic planning, operating management, report reliability, legal compliance, and asset safety play a significant role in alleviating the effect of uncertainty on investment inefficiency . Heterogeneity analysis reveals that the moderating effect of internal control is significant for state-owned enterprises (SOEs), but insignificant for foreign-funded firms. Overall, this study highlights the importance of strengthening corporate internal control in preserving investment efficiency during periods of heightened uncertainty.</p>