Abstarct: Abstract In this research, the relationship between the ability to accept risk and the behavioral tendencies of investors has been investigated. The statistical population of this research is real investors active in Tehran Stock Exchange. Data has been collected by field method and through questionnaire. The results indicate that there is a significant relationship between investors' risk tolerance and some behavioral tendencies, including overconfidence, maximization, and avoidance of regret. Also, the age factor was found to be effective in the maximization tendency and the education level factor in the tendency to overconfidence, regret avoidance and trust in others.