With budgets shifting to creators, marketers need a reliable map of the levers that drive Gen Z purchases, particularly in the competitive masstige fashion sector. This systematic literature review synthesizes 17 peer-reviewed studies (2019–2025) on how influencer marketing drives Gen Z purchase behavior in masstige fashion. The study maps mechanisms linking creator attributes, content formats, and platform dynamics to perceived value, trust, parasocial closeness, social proof, and FOMO, translating engagement into purchase intention, eWOM, and loyalty. Results highlight creator–brand fit, authenticity, and platform-native storytelling as the most consistent levers. Managerially, brands should prioritize credible creators, value-rich narratives, and transparent “drop” mechanics. Managerial implications are provided, and research possibilities are presented to advance the field.