Abstract: The rapid development of social media, especially TikTok, has driven the popularity of affiliate marketing through influencers. Generation Z—young, proactive, and tech-savvy consumers—has become a segment strongly influenced by these marketing strategies. This study proposes a research model to examine the influence of TikTok influencers on the purchasing behavior of Gen Z in Ho Chi Minh City via affiliate marketing as an intermediary mechanism. Based on the theoretical foundations of planned behavior and emotion, the proposed model connects factors such as influencer popularity, congruence (fit), and credibility with purchasing behavior. Simultaneously, the model incorporates mediating factors like Fear of Missing Out (FOMO) and emotional responses to elucidate the mechanism by which influencer impact is converted into consumer purchase decisions.