By utilizing the Fixed effect and GMM estimators for a sample of 57 Islamic banks and 102 conventional banks from 10 countries for the period 2002–2018, we examine the effect of the audit committees' and Sharia committees' effectiveness on the bank risk-taking behavior and its transmission mechanisms. The results reveal that an audit committee's independence, number of meetings, and financial expertise negatively affect conventional banks' risk-taking, suggesting that the high effectiveness of their audit committees may constrain banks' risk-taking activities. However, no such relationship is evident or observed case of Islamic banks. Instead, with a different transmission mechanism, the proportion of female members and the financial expertise in the Sharia committees negatively affect risk-taking, but the Sharia committee size positively affects risk-taking in Sharia banks. These results indicate that a Sharia committee's high effectiveness can constrain risk-taking behaviors in Islamic banks.