Group Rally1 is a technical specification of rally car for use at the highest level of international rallying in the World Rally Championship (WRC) as determined by the FIA. Despite the use of the word 'Group' in the name, there are not multiple classes or subclasses of car and so 'Rally1' may be used alone with the same definition. Rally1 cars were used for the first time in the 2022 WRC season and replaced the outgoing World Rally Car used in the manufacturer's championship. Though they may run on any individual rally as permitted by the organiser, they are not be used in any other championship.

The World Rally Championship is an international rallying series owned and governed by the FIA. Inaugurated in 1973, it is the second oldest of the FIA's world championships after Formula One. Each season lasts one calendar year, and separate championship titles are awarded to drivers, co-drivers and manufacturers. There are also two support championships, WRC2 and WRC3, which are contested on the same events and stages as the WRC, but with progressively lower maximum performance and running costs of the cars permitted. Junior WRC is also contested on five events of the World Rally Championship calendar.