In today's competitive market, gaining an appropriate position in the mind of the consumer, in such a way that the consumer is loyal to the company, is of great importance, and , advertising is considered ineffective. The purpose of this research is to explain the role of brand promotion on customer loyalty with with mediating role of level five leadership. This research is an applied research. The statistical population of this research includes Parsian Bank customers. The research tool includes a researcher-oriented questionnaire. To check the instrument's validity, face validity and content validity (by measuring the ratio of content validity and content validity index and construct validity by performing exploratory factor analysis) were used. The non-random and available sampling method was selected according to the Morgan table of 384 people due to the uncertainty of the statistical population. The data were analyzed using SPSS25 software and Smartpls3 software by applying appropriate statistical tests, according to the research hypotheses. The results of his research showed that the identified variables were valid in the form of a paradigmatic model. The value of SRMR statistic is also equal to 0.05, which is less than 0.08, which indicates the good fit of the model. The value of NFI is also equal to 0.81. Although the value of this statistic should be more than 0.9 to have a satisfactory fit, a value of more than 0.8 also indicates a good fit.