Car boot sales or boot fairs are a form of market in which private individuals come together to sell household and garden goods. They are popular in the United Kingdom, where they are often referred to simply as 'car boots'.

Some scientific research has studied people's shopping habits at car boot sales. These groups of scientists see the rotation of surplus household stock as essential as it prevents waste and disposal costs, and also produces a small community where thriftiness and entrepreneurship flourish.

The term "car boot sale" refers to the selling of items from a car's boot. Although a small proportion of sellers are professional traders selling goods, or indeed browsing for items to buy, most of the goods on sale are used personal possessions. Car boot sales are a way of attracting a large group of people in one place to recycle useful but unwanted domestic items that otherwise might have been thrown away. Car boot sales generally take place in the summer months. However, in a growing trend, indoor boot sales, and all-year hard-standing outdoor boot sales, are now appearing in some parts of the UK. Items for sale are extremely varied, including for example antiques and collectables, as in a flea market. Car boot sales are also very popular in parts of Australia, and have a growing presence in mainland Europe.