MacEvoy (or MacAvoy) is the phonetic anglicisation of Mac Fhiodhbhuidhe, possibly from the Irish fiodhbhadhach, "man of the woods". The most prominent family of the name originally held power in the barony of Moygoish in modern Co. Westmeath, but migrated south-west, where they became one of the well-known "Seven Septs of Leix", ruling over an area in the parishes of Mountrath and Raheen in Co. Laois. In the early seventeenth century, the most important leaders of the family were forcibly transported to Co. Kerry, together with other members of the "Seven Septs", but the surname remains numerous in the Laois/Westmeath region. In the north of the country, MacEvoy was used as an erroneous equivalent of Mac Giolla Bhuidhe, "son of the fair-haired youth", a Donegal name usually anglicised as "McIlwee" or "MacKelvey", and of Mac an Bheatha, "son of life" (MacVeigh), a surname common in the Armagh/Louth region.
In 1890 the surname was recorded as most common in the Armagh/Louth area.
.Francis MacEvoy (1751-1804) was President of the Royal College of Surgeons of Ireland.
Eleanor McEvoy (1967 - ) is one of a group of extremely successful women singer-songwriters to emerge in Ireland in the early 1990s. She began her career as a violinist in the National Symphony Orchestra, but went solo in 1991 after the release of her first record. She has won numerous awards.