This chapter provides an integrative overview of food neophobia across the lifespan, extending beyond childhood to examine its biological, psychological, and sociocultural determinants. Food neophobia is introduced as an adaptive response rooted in evolutionary pressures related to avoiding potential dietary risks. We then outline its developmental trajectory: rising in early childhood, generally decreasing through adolescence and adulthood, and potentially reemerging in later life. Biological and sensory contributors are discussed, including genetic predispositions and individual differences in taste, smell, and texture responsiveness, which influence willingness to try unfamiliar foods. Psychological factors such as anxiety, risk perception, and personality traits add further variability in avoidance tendencies. The social environment is considered through the roles of family feeding practices, peer modeling, and broader cultural frameworks that shape familiarity, expectations, and meanings associated with food. The chapter also reviews the development and adaptation of measurement instruments used to assess food neophobia across different populations. We conclude by emphasizing the relevance of food neophobia for dietary variety, nutritional well-being, and public health, calling for approaches that integrate sensory, behavioral, and cultural levels of analysis within nutrition and health sciences. Future research should especially address vulnerable populations, diversify cross-cultural perspectives, and refine assessment tools to better capture attitudes toward novel and sustainable foods.