Hat-making or millinery is the design, manufacture and sale of hats and other headwear. A person engaged in this trade is called a milliner or hatter.

Historically, milliners (typically women shopkeepers) produced or imported an inventory of garments for men, women, and children and sold these garments in a millinery shop.

The term "milliner" or "Milener" originally meant someone from Milan, in northern Italy, in the early 16th century. It referred to Milanese merchants who sold fancy bonnets, gloves, jewellery and cutlery. In the 16th to 18th centuries, the meaning of "milliner" gradually changed in meaning from "a foreign merchant" to "a dealer in small articles relating to dress". Although the term originally applied to men, from 1713 "milliner" gradually came to mean a woman who makes and sells bonnets and other headgear for women.

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