A duty-free shop (or store) is a retail outlet whose goods are exempt from the payment of certain local or national taxes and duties, on the requirement that the goods sold will be sold to travelers who will take them out of the country, who will then pay duties and taxes in their destination country (depending on its personal exemption limits and tariff regime). Which products can be sold duty-free vary by jurisdiction, as well as how they can be sold, and the process of calculating the duty or refunding the duty component.

Tax Free World Association (TFWA) announced that in 2011 Asia-Pacific, with 35 percent of global duty-free and travel retail sales, has more duty free than Europe and Americas, with these regions accounting for 34 percent and 23 percent respectively. 31 percent of sales came from the fragrances and cosmetics category, followed by the wine and spirit category with 17 percent and then comes tobacco products.

However, some countries impose duty on goods brought into the country, though they had been bought duty-free in another country, or when the value or quantity of such goods exceed an allowed limit. Duty-free shops are often found in the international zone of international airports, sea ports, and train stations but goods can also be bought duty-free on board airplanes and passenger ships. They are not as commonly available for road or train travelers, although several border crossings between the United States and both Canada and Mexico have duty-free shops for car travelers. In some countries, any shop can participate in a reimbursement system, such as Global Blue and Premier Tax Free, wherein a sum equivalent to the tax is paid, but then the goods are presented to customs and the sum reimbursed on exit.

Duty-free are abolished for intra-EU (inside the EU tax union) travelers but are retained for travelers whose final destination is outside the EU. They also sell to intra-EU travelers but with appropriate taxes.

The world's largest airport by duty-free sales is South Korea's Incheon Airport, with US$1.85 billion in 2016, narrowly overtaking Dubai Duty Free with 2016 sales of $1.82 billion.