This study examines the impact of stock liquidity on stock price crash risk and the moderating role of institutional blockholders in Vietnam's stock market. Using firm-level data from 2010 to 2020, the research finds that stock liquidity increases crash risk, with the relationship being stronger in firms owned by institutional blockholders. Moreover, intensive selling by institutional blockholders in the future positively moderates the relationship between liquidity and crash risk. The study uses two measures of crash risk: negative skewness of firm-specific weekly returns (NCSKEW) and down-to-up volatility of firm-specific weekly stock returns (DUVOL). Stock liquidity is measured by adjusted Amihud illiquidity. The two-stage least squares method is used to address endogeneity issues. The findings suggest that high liquidity encourages blockholders to exit upon receiving private bad news, leading to stock price crashes. The study contributes to the literature by showing that blockholder activities can explain the relationship between liquidity and crash risk. Practical implications include the need for firm managers to avoid bad news accumulation and practice timely information disclosures, while investors should be mindful of the risks associated with liquidity and blockholder trading. The study highlights the importance of institutional investors in emerging markets like Vietnam, where retail investors dominate and exhibit herding behavior. The results suggest that institutional blockholders' trading based on private information can amplify stock price crashes, especially in high-liquidity environments. The study also indicates that foreign institutional blockholders have a stronger impact on crash risk than domestic ones. Overall, the findings underscore the complex relationship between stock liquidity, institutional ownership, and stock price crash risk in emerging markets.This study examines the impact of stock liquidity on stock price crash risk and the moderating role of institutional blockholders in Vietnam's stock market. Using firm-level data from 2010 to 2020, the research finds that stock liquidity increases crash risk, with the relationship being stronger in firms owned by institutional blockholders. Moreover, intensive selling by institutional blockholders in the future positively moderates the relationship between liquidity and crash risk. The study uses two measures of crash risk: negative skewness of firm-specific weekly returns (NCSKEW) and down-to-up volatility of firm-specific weekly stock returns (DUVOL). Stock liquidity is measured by adjusted Amihud illiquidity. The two-stage least squares method is used to address endogeneity issues. The findings suggest that high liquidity encourages blockholders to exit upon receiving private bad news, leading to stock price crashes. The study contributes to the literature by showing that blockholder activities can explain the relationship between liquidity and crash risk. Practical implications include the need for firm managers to avoid bad news accumulation and practice timely information disclosures, while investors should be mindful of the risks associated with liquidity and blockholder trading. The study highlights the importance of institutional investors in emerging markets like Vietnam, where retail investors dominate and exhibit herding behavior. The results suggest that institutional blockholders' trading based on private information can amplify stock price crashes, especially in high-liquidity environments. The study also indicates that foreign institutional blockholders have a stronger impact on crash risk than domestic ones. Overall, the findings underscore the complex relationship between stock liquidity, institutional ownership, and stock price crash risk in emerging markets.