Dairy products are generally defined as foodstuffs produced from milk. They are usually high-energy-yielding food products. A production plant for such processing is called a dairy or a dairy factory. Raw milk for processing generally comes from cows, but occasionally from other mammals such as goats, sheep, water buffalo, yaks, or horses. Dairy products are commonly found in European, Middle Eastern and Indian cuisine, whereas they are almost unknown in East Asian cuisine.

Dairy may cause health issues for individuals with lactose intolerance and milk allergies.

Vegans and some vegetarians avoid dairy products due to a variety of ethical, dietary, environmental, political, and religious concerns.

Eggs are sometimes categorized as dairy, defining dairy as "food that is produced by animals (other than meat)" rather than as milk specifically. Defining dairy as limited to milk products, however, is more common.