In the current digital era, the swift expansion of social media platforms, online shopping, and digital advertising has transformed how businesses engage with consumers. One of the most potent psychological tactics in this environment is Fear of Missing Out (FOMO). This study explores the Rhetoric of Fear of Missing Out (FOMO) in digital marketing, analysing its impact on consumer decision-making, the psychological mechanisms it employs, and the ethical concerns it raises. Grounded in social comparison and loss aversion theories, this research examines how marketers use FOMO-driven strategies such as scarcity, urgency, and social pressure to influence consumer behavior. Through case studies, the study highlights how FOMO tactics tap into deep-seated human fears of exclusion and loss, often leading to impulsive purchasing decisions. However, while effective, these strategies pose ethical challenges, including increased consumer anxiety, financial strain, and environmental consequences due to overconsumption. The study argues for greater transparency and ethical responsibility in digital marketing practices to balance persuasion with consumer well-being.