the main purpose of the present study is the Effect of the Moderating Role of Internal Financing, on the relationship between Corporate Life Cycle and social responsibility in firms accepted in Tehran Stock Exchang. To this end, Four hypotheses were defined in the study. In order to test the hypotheses of the study, the statistical measure of Multivariate Linear Regression Analysishas been employed. The type of data utilized to test the respective research hypotheses was panel data. Sample population of the study included 73 firms accepted in Tehran Stock Exchangeusing accessible sampling method whose data were investigated over years 2007 to 2016. According to the results of the study, corporate social responsibility in different stages of the life cycle (Start-up, growth, maturity and decline) are significantly different. also, Internal Financing has an effect on Corporate Social Responsibility. The results also show that in the Internal Financing as a Moderating has an effect on the intensity Relationship between Corporate Life Cycle (growth and decline) and Corporate Social Responsibility.