Buttermilk is one of the most important by‐products of the dairy industry. Approximately 2 million tonnes were produced within the European Union in 2015. Recently, buttermilk has gained increasing attention due to its unique structure, characteristics, and promising applications. It is classified as a functional food because it contains water‐soluble components, polar lipids and milk fat globule membranes. This review is focused on buttermilk composition, global production, and applications in several food industries. Furthermore, the beneficial characteristics of buttermilk for human health are highlighted.