Today, in many countries, particularly the developing countries, economic reform, such as privatization, is considered a strategic approach. The more governments grow, the tighter the competitions become in the market, so, it appears that some fields should be privatized in order to create competition. By moving towards privatization and the changes in competition methods and the presentation of the World Trade, the importance of management accounting is more pronounced. This research is based on the Contingency Theory of Anderson and Lenan (1999) and it investigates the relation of the level of privatization on the performance of privatized companies with emphasis on the use of management accounting tools as an intermediary variable. The data, related to management accounting tools and used by the companies during 6 years, was collected through questionnaires and the data related to privatization and financial performance was collected using the information registered in the statements of 48 accepted companies on Tehran’s Stock Market whose dates of acceptance are before 1387 and were continuously active until 1392. This data was analyzed by PLS 2014. The results indicate a positive relation between financial performance and privatization, and management accounting, as an intermediary variable, enhances this relation. Furthermore, the use of management accounting tools has a positive relation with the financial performance and the privatization of companies.