As the field of esports continues to rapidly evolve, understanding the complex relationship between nutrition and cognitive performance has become increasingly paramount. This chapter explores the intricate mechanisms by which various macronutrients, micronutrients, and bioactive compounds influence the cognitive processes that underpin successful competitive gaming. Drawing from the latest research in cognitive psychology, neuroscience, and sports nutrition, the chapter delves into the unique cognitive demands of esports, which frequently exceed the requirements of traditional laboratory-based assessments. Key cognitive domains discussed include sustained attention, working memory, decision-making, and executive function—all of which exhibit distinct neurophysiological signatures and are differentially affected by nutritional factors. The chapter examines how glucose metabolism, omega-3 fatty acids, caffeine, and other substances can enhance or impair these cognitive abilities, with implications for optimizing in-game performance. Additionally, the chapter highlights the critical role of hydration status and sleep quality in supporting cognitive function under the extreme physiological demands of competitive gaming. Beyond acute nutritional interventions, the chapter also explores the influence of long-term dietary patterns on neuroplasticity and cognitive adaptation to the unique challenges of esports. Emerging research in nutrigenomics and the gut–brain axis suggests promising avenues for developing individualized nutritional strategies to support the cognitive resilience of professional gamers. Overall, this chapter provides a comprehensive overview of the current state of knowledge in this rapidly evolving field, offering practical insights to guide the development of evidence-based nutritional frameworks for the esports industry.