Food neophobia is characterized by the reluctance to try new or unfamiliar foods. It is commonly observed across the lifespan but is especially prevalent during childhood. Food neophobia may once have acted as an evolutionary protective trait, preventing the consumption of potentially harmful or toxic substances. Today, by contrast, the avoidance of new foods acts as a maladaptive behavior, negatively impacting diet diversity and quality. This chapter begins by defining what food neophobia is and how it is measured in children and adults. We then examine the relationship between food neophobia and dietary intakes, drawing on evidence from children, adolescents, and adults. We examine how food neophobia affects the consumption of key food groups, most notably fruits and vegetables, as well as dietary variety, nutrient adequacy, and overall diet quality. We investigate the potential mechanisms underlying the negative associations between food neophobia and diet quality, including differences in sensory sensitivity and food choice motives. We briefly discuss the evidence examining the link between food neophobia, weight status, and broader health outcomes. Finally, we evaluate the different interventions designed to mitigate food neophobia and encourage food acceptance. By synthesizing current research, this chapter highlights the pressing need to address food neophobia as a barrier to healthy eating. Reducing food neophobia through targeted interventions could play a crucial role in improving dietary variety, adherence to dietary guidelines, and long-term health outcomes.