Chocolate milk is a type of flavoured milk made by mixing cocoa solids with milk (either dairy or plant-based). It is a food pairing in which the milk's mouthfeel masks the dietary fibres of the cocoa solids.

The liquid carbohydrates in milks like cow milk, or oat milk, may be sufficient on its own to mask the bitterness from the cacao's theobromine. However, most often additional sweeteners are added to make the drink taste sweet.

However, the particles from cocoa solids in homemade chocolate milk will quickly sediment to the bottom. So the solution should be shaken or stirred before consumption to avoid uneven concentration. This is not a problem in some ready to drink chocolate milks.

Sugar used in commercial chocolate milk serves as a preservative, and the energy from the sugar also makes it a convenience food. It can also be made at home by blending milk with cocoa powder and a sweetener (such as sugar or a sugar substitute), melted chocolate, chocolate syrup, or a pre-made powdered chocolate milk mix. Other ingredients, such as starch, salt, carrageenan, vanilla, or artificial flavoring are sometimes added. To add nutritional value to the product, sometimes some minerals like zinc oxide or iron are added.

In New York City, school food officials report that nearly 60 percent of the 100 million cartons served each year contain fat-free chocolate milk.

Some nutritionists have criticized chocolate milk for its high sugar content and its relationship to childhood obesity. Because chocolate milk can contain twice as much sugar as plain low-fat milk from added sugars, some school districts have stopped serving the product altogether.

Dark chocolate milk has more cocoa solids than conventional chocolate milk. However, added sugar can still contribute to health problems.

Drink mixes of cocoa powder and a sweetener can be either homemade or commercially manufactured.