The traditional methods of searching for information and buying items have become obsolete, and have created new social and economic consequences in various fields such as marketing and relevant activities due to social media in today's world; hence, the present study aimed to explain the roles of social media marketing activities in improving customer commitment by considering the role of brand equity as a mediating variable. The statistical population consisted of customers of Digikala online store as members of the Instagram page of this store. Due to the unknown population size, the statistical sample was determined to be equal to 384 according to the Morgan table. The data collection tool of the study included a standard questionnaire, and the data analysis method was based on confirmatory factor analysis and structural equations. The results indicated that social media marketing activities had positive and significant effects on brand equity dimensions (brand awareness, and brand image) that in turn had a positive and significant effect on customer commitment. Social media marketing affected customer commitment directly and mediated by brand equity.