Nowadays, the growing importance of marketing activities in social media (SM) has attracted a lot of attention in researches and industries around the world. Many companies consider flow theory important to strengthen their customer relationships in the online environment. Flow Theory experience can predict satisfactory outcomes for online interactions between consumers and companies. This study examines the moderating role of flow theory on the relationship between marketing activities and customer responses. A total of 384 customers who experienced online shopping from “DigiKala,” one of the most pioneer online retailers in Iran, answered the survey. Data collection was done through the questionnaires, and structural equation modeling was used to analyze the data of this study. The results showed that marketing activities in social media have a significant positive effect on brand equity and customer response. Also, flow theory moderates the impact of marketing activities on social media, brand equity, and customer response, significantly. Finally, brand equity affects customer responses in the present research.