The Isetta is an Italian-designed microcar built under licence in a number of different countries, including Spain,Belgium,France,Brazil,Germany, and the United Kingdom. Produced in the post-World War II years, a time when cheap short-distance transportation was most needed, it became one of the most successful and influential city cars ever created. Because of its egg shape and bubble-like windows, it became known as a bubble car, a name later given to other similar vehicles.

The BMW Isetta was in 1955 the world's first mass-production 3-Litres/100km car. It was the top-selling single-cylinder car in the world, with 161,728 units sold.

The car originated with the Italian firm of Iso SpA. In the early 1950s the company was building refrigerators, motor scooters and small three-wheeled trucks. Iso's owner, Renzo Rivolta, decided he would like to build a small car for mass distribution. By 1952 the engineers Ermenegildo Preti and Pierluigi Raggi had designed a small car that used the scooter engine^{[citation needed]} and named it Isetta—an Italian diminutive meaning little ISO.