ABSTRACT Background Skin is the largest organ of the human body, and acts as a fundamental barrier. Beyond its protective role, it serves as a key immune organ, mediating immune surveillance and regulation. Exposure to environmental factors such as mechanical trauma, detergents, air pollution, and microbial dysbiosis can compromise the skin barrier triggering the release of pro‐inflammatory cytokines that contribute to the pathogenesis of allergic diseases including atopic dermatitis (AD). Nutrition profoundly impacts skin health, influencing cell proliferation, tissue repair, and immune functions. Methods This review aims to explore the relationship between diet and skin barrier function, with a specific focus on AD. Results The evidence on micro‐ and macronutrients, probiotics, and various dietary patterns, highlighting their potential to enhance or impair skin barrier integrity, provides a comprehensive exploration of how diet may serve as a modifiable factor in supporting skin health and preventing allergic diseases. This review also outlines directions for improving future research. Conclusion Diet is an important modifiable factor in preserving skin barrier integrity and may contribute to the prevention and management of AD. However, inconsistent evidence precludes definitive dietary recommendations, highlighting the need for further research.