• The phenomenon of tax avoidance is one of the most important phenomena that have received great attention from researchers recently. Rather, it has become one of the global phenomena, and this phenomenon gain more importance in developing environments and countries, including Egypt, and this phenomenon affects many variables that ultimately affect the performance of business establishments. The current study attempts to identify the nature of the relationship between tax avoidance and investment efficiency. The results are the acceptance of the first hypothesis of the study “tax avoidance negatively affects the efficiency of investment decisions.” This result can be interpreted as tax avoidance magnifies the problem of information asymmetry and increases agency problems as the management would have extensive investing to achieve their personal interests. • Social responsibly disclosure is considered one of the important indicators to identify the extent of the firm's ability to survive and be sustainable, so the owners always push the management to adopt a vision that is based on sustainability, disclosure, and transparency. The current study attempts to identify the nature of the relationship between disclosure of social responsibility and investment decisions efficiency. The results indicate the acceptance of the second hypothesis of the study “disclosure of social responsibility positively affects the efficiency of investment decisions,” and this can be explained by considering that the high performance of social responsibility may allow managers to achieve more gains for stakeholders, which may lead to a more rational use of financial resources and improve the efficiency of investment.