This study examines the empirical impacts of moderating (MO) and mediating (ME) variables in business research, within the context of auditing reports. size, complexity of the operation, and risk of the firm were selected as the independent variable, moderating variable, and mediating variable, respectively. The selection was attempted over 15 years of research (1455 year-firm data) for the firms listed on the Tehran Stock Exchange (TSE). The following techniques were employed for testing the hypothesis: Pearson correlation, Levin, Lin, and Chu test, Hausman unit root, and multiple regression. The results revealed that there is a significant relationship between the size of the firm and the type of the auditing report. Moreover, a significant relationship between the size of the company and the type of auditing report is shown in the inventory value of the moderating variables. Furthermore, the same has been displayed in return on the assets and institutional ownership of the mediating variables. However, inventory and institutional ownership demonstrate a significant statistical relationship when moderating and mediating variables are considered simultaneously. The implication of this study is to demonstrate the moderating and mediating variables as significant impediments in the type of auditing report. This would change the design, theory, and implications of this research.