We examine whether Islamic banks are more likely to be conservative in their financial reporting than conventional banks, as well as how Islamic banks' unique corporate governance system affects accounting conservatism behaviors. Using a large sample of Islamic banks and their matched non‐Islamic banks; based on total assets and geographic location, in 15 countries, we find Islamic banks are more likely to deploy accounting conservatism as measured by loss avoidance, abnormal loan loss provisions, and C‐score, respectively. Islamic banks are about 95% more likely to be more conservative in accounting practices than their counterparts, depending on different model specifications. In addition, we report several board characteristics, such as size, independence, reputation, tenure, and diversity, are important determinants of accounting conservatism in Islamic banks. This relationship indicates certain board traits lead to greater monitoring roles, consequently reducing unethical behavior and increasing the degree of conservatism in accounting practices.