This study explores how artificial intelligence (AI) in marketing strategies influences customer engagement on Vietnam’s leading e-commerce platforms, including Shopee, Tiki, Lazada, and Sendo. Adopting a qualitative case study approach, the research draws on 20 semi-structured in-depth interviews—8 with marketing professionals and 12 with frequent e-commerce users—to provide a multi-perspective understanding of AI’s role in shaping engagement behaviors. The findings reveal that AI significantly enhances customer engagement by enabling personalized product recommendations, real-time communication through chatbots, and proactive interactions based on predictive analytics. Notably, 90% of interviewed customers expressed a strong preference for AI-curated content, citing higher relevance and convenience. AI-powered chatbots, which handle over 80% of customer inquiries on platforms like Lazada, were praised for their speed and 24/7 availability. Additionally, marketing experts highlighted that AI-driven predictive tools have increased customer conversion rates by 15–25% in selected campaigns. However, the study also uncovered critical concerns around ethical practices and data privacy. Approximately 50% of customer participants expressed discomfort with how much personal information is collected and the lack of transparency in AI usage. In contrast, marketing professionals acknowledged this concern and emphasized the need for clearer communication and data protection policies..