The A-segment is the first category in the passenger car classification system defined by the European Commission. It is used for city cars, the smallest category of passenger cars defined.

A-segment sales represented approximately 4.2% of the European market in 2024. It is approximately equivalent to the kei car class in Japan.

As of 2021, the A-segment category size spans from approximately 2.7 metres (110 in) to 3.7 metres (150 in).

Body styles for A-segment cars in Europe have historically nearly always been hatchbacks. But as crossovers gain popularity, new models have begun to shift to resemble crossovers. Examples of crossover city cars include Suzuki Ignis and Toyota Aygo X. Other body styles such as sedans are not present in this segment because these shapes largely prove impractical at typical A-segment dimensions.

A-segment cars are traditionally offered with manual transmission as the sole transmission option. Beginning in the 2010s, automatic options are increasingly available. Some newer models most often utilize CVTs, while a small number of manufacturers also offer automated manual transmissions.

The engines of A-segment cars commonly range from 1.0 to 1.4 litres, either in inline-four or three configuration. Newer models may have turbocharged and/or hybrid engines with a particular emphasis on higher fuel efficiency.

In 2020 the ten highest selling A-segment cars in Europe were Fiat Panda, Fiat 500, Toyota Aygo, Renault Twingo, Volkswagen Up!, Hyundai i10, Kia Picanto, Peugeot 108, Citroën C1 and Suzuki Ignis.

100,000 - 200,000 sales