Brands are considered as valuable assets of a company both economically and strategically. Thus, having customers who are loyal to a brand is one of the main goals of businesses companies. Identifying and anticipating the customers’ needs are vital to the enterprises gaining competitive advantage and market segmentation. Maintaining and enforcing customers’ loyalty is a strategic challenge for companies seeking to keep and promote their competitive status in the market. High brand loyalty of the customers generates competitive advantage for the company and it increases the income and decreases the costs of marketing. In addition to increasing the market share, loyalty allows to ask for higher prices compared with its competitors. This study seeks to investigate the factors influencing customer loyalty to sport brands. The statistical population of this research was Tehran city. Using simple cluster sampling, 502 customers of four known brand sports, i.e. Nike, Puma, Adidas, Reebok, and Fila were chosen. Furthermore, a questionnaire, which assessed seven variables including reputations, brand name, brand image, brand loyalty, customer satisfaction, promotion and the price was used and the hypotheses were analyzed using statistical tests such as Kolmogorov-Smirnov test (K-S test), Spearman correlation, simultaneous linear regression and binomial test. The findings suggested that the brand name has a strong correlation with brand loyalty. Moreover, variables such as reputation, brand image, customer satisfaction, price and promotions also have positive and significant effect on the brand loyalty.