Nestor is, apart from a given name, also found as a surname borne by Irish and Estonians.
In Ireland, it was derived as a shortened form of Mac Girr an Adhastair, meaning son of the short man of the bridle. It was sometimes shortened to Mac an Adhastair. The surname is most common in County Galway and County Clare. The clan were natives of Corcomroe in the latter county, which in the Middle Ages formed the north-westernmost territory of the kingdom of Thomond. The Mac Girr an Adhastair were associated with the local lords, the Ó Lochlainn family.
Notable people with the surname include:
Agnes Nestor (1880–1948), American labor leader and social reformer
Daniel Nestor (born 1972), Canadian grand slam winning tennis player
Eddie Nestor (born 1964), broadcaster and comedian
Eiki Nestor (born 1953), Estonian politician
Ernie Nestor (1946–2025), American basketball coach
Ion Nestor (1905–1974), Romanian archaeologist
John Nestor (1912–1999), American medical officer and whistleblower
John Nestor (American football) (born 2005), American football player
Kelly Nestor (born 1968), Australian newsreader
Pam Nestor (born 1948), British lyricist, singer and actress
Rodrigo Nestor (born 2000), Brazilian footballer