Purpose: The main objective of this study is to investigate the relationship between audit committee characteristics and comparability of financial statement with the moderating role of audit firm size and corporate governance. Methods: In this study, have been investigated 56 firms listed on Tehran stock exchange during the years 2013 to 2017 and To estimate research hypothesis, is used a multivariable regression model. Results: Results of the study indicate that there is a negative and significant relationship between audit committee characteristics and financial statements comparability. However, audit firm size has a negative effect on relationship between audit committee characteristics and financial statement comparability and finally, board size has a positive effect on relationship between audit committee expertise and financial statement comparability and independent board has a negative effect on relationship between audit committee size and financial statement comparability. Conclusions: Reducing financial statement comparability stem from less effectiveness audit committees. Contribution: Despite the effect performance of audit committees on quality characteristics of financial statements, need attention to the effectiveness of audit committees is very important.