GRO or General Register Office is known for civil registrations of events such as births, stillbirths, marriages, deaths, civil partnerships and adoptions. There are three main GRO offices in the United Kingdom: one for England and Wales, one for Northern Ireland and one for Scotland.

The responsibilities of the GRO are to correctly and accurately administer and register births, marriages and deaths according to current Acts such the Civil Partnership Act and the Gender Recognition Act 2004.

It is within the General Register Office that a copy of all registrations of birth, death, marriage, adoption and civil partnership is retained at a national level.

In England and Wales the GRO was established in 1836 in preparation for civil registration, which began in 1837. In 1972 the GRO was integrated into the Office of Population Censuses and Surveys (OPCS), and then later became part of the Office of National Statistics (ONS).

The General Register Office is also involved in the collection and publication of information relating to population, such as the current population size, and the geography of the population, and censuses.

The Registrar General is the head of each General Register Office.