In this study, the relationship between market power and industry-level competition with earnings sustainability were investigated. The purpose of this study was to evaluate the market power and industry-level competition and earnings sustainability in listed companies on the Tehran Stock Exchange. To achieve this goal, the Herfindahl-Hirschman Index, Lerner and Adjusted Lerner index as competition measures were considered. Our sample consists of 155 firms for the period 1386 to 1391. In addition, there is an inverse relationship between the Lerner Index and earnings stability, can mean the direct relation between the level of competitiveness and sustainability of benefits should be considered.