Hoy is a Scottish and Irish surname.
The Irish origin of the name is derived from "Ó hEochaidh".
Other surnames developed from "Ó hEochaidh" include: McKeogh, Kehoe, Hoey, Haughey, Haugh and Hough.
Hoy is sometimes considered to be a variant of Haughey, and it is very common in Ulster.
The first recording of the surname in Ireland is of one Elizabeth, daughter of Leuise and Martha Hoy, on 8 February 1646, at Holy Trinity (Christchurch), Cork.