Chronic inflammation plays an imperative role in the onset and progression of chronic diseases including diabetes, hypertension, cancer, allergies, and asthma. Diet can modulate different stages of inflammation since it is a rich source of antioxidants and bioactive compounds. Flavonoids are bioactive compounds abundantly found in various food groups such as vegetables, fruits, nuts, cereals, and beverages. Recent work on flavonoids has unveiled their potential to regulate or inhibit inflammation. This is attributed to their anti-inflammatory, anti-oxidative, and immune-modulatory properties, making flavonoids an invaluable component in nutraceutical, pharmaceutical, and medicinal applications. However, information related to their anti-inflammatory mechanism is still not well understood. The current review is an attempt to elaborate chemical structure, dietary sources, and anti-inflammatory properties of flavonoids against allergic diseases.