Iran's banking industry has faced a wide range of changes during recent years and its banks' performance has been affected by these changes. On the one hand, the entry of private banks to the industry has made various changes in the industry's concentration and the market share of banks, on the other hand, banking technologies and strengthened competitive environment have led banks to increase efficiency and improve their performance. Given the importance of competition and efficiency in different components of the economy, the present study aims to investigate the competitiveness of private banks over the period 2005 to 2017. For this purpose, according to Panzar-Rosse model in the framework of panel data models, required data are collected from all private banks, then the competitiveness of private banks is calculated using the Panzar-Rosse model. According to the results, markets of Iran’s private banks are involved in monopolistic competition during the underlying time period.