“Carotenoid” refers to most natural pigments widely distributed in nature. Terrestrial and aquatic photoautotrophs universally synthesize them. Moreover, some insects and microorganisms are also capable of synthesizing carotenoids. Most carotenoids possess a C40 hydrocarbon skeleton with conjugating double bonds; some undergo cyclization at the ends. Humans mainly obtain carotenoids by consuming plant-based foods and can accumulate many carotenoids. Their importance for human health is immense, especially considering the challenge of accessing fresh, consumable foods. Carotenoids are well known for their powerful antioxidant properties, effectively tackling harmful free radicals and reducing oxidative stress. This book chapter aims to share insights into the structure, bioavailability, and some impactful carotenoid roles discovered so far. It explores the health benefits of carotenoid consumption, focusing on their potential to prevent chronic diseases, like cardiovascular and neurodegenerative diseases, diabetes, and certain cancers. It also investigates how carotenoids operate, influencing physiological functions such as regulating the immune system and alleviating inflammation. Further, the antioxidant properties of carotenoids and their derivatives have been exploited in the nutraceutical, cosmetic, and pharmaceutical industries. As we face challenges in obtaining fresh and nutritious foods, understanding the benefits of carotenoids becomes crucial for our overall health. Animals and humans do not synthesize carotenoids and are consumed only through diet.