This study aims to investigate the moderating role of gamification in the relationship between social media marketing and customer-brand engagement, focusing on users of the SnappFood application in Tehran. Applied in purpose and descriptive-survey in nature, the research targeted all active SnappFood users in Tehran (unknown population size). Based on Cochran’s formula, a sample of 385 participants was selected using convenience sampling. Data were collected via standardized questionnaires measuring social media marketing and customer-brand engagement (Chepong et al., 2023) and gamification (Dessandro et al., 2022). The validity of the instruments was confirmed, and their reliability was established at a desirable level using Cronbach’s alpha coefficient. Data analysis and hypothesis testing were conducted using SPSS version 22 and SmartPLS version 4 within a structural equation modeling (SEM) framework. The findings revealed that all five dimensions of social media marketing (entertainment, interaction, trendiness, customization, and word-of-mouth promotion) exert a positive and significant effect on customer-brand engagement. Furthermore, gamification significantly moderates only the relationship between entertainment and customer-brand engagement, while showing no significant moderating effect on the impact of the other dimensions. Accordingly, it is recommended that managers of service platforms strategically integrate gamified elements into entertainment-oriented campaigns, while refraining from implementing them within interactive tools, customization features, or word-of-mouth mechanisms. This research provides a practical framework for optimizing digital marketing strategies within the food delivery ecosystem.