An Irish surname of recent introduction. From O Gallchobhair, 'descendant of Gallchobhar,' meaning 'valorous victor,' or 'foreign help' (Woulfe). The name is sometimes apocopated O Gallchu, giving Gallahue.

The surname Gallagher is of Irish origin. The Irish Gaelic form of Gallagher (or O’Gallagher) is O’Gallichobhair, and derives from the Gaelic word ‘gallchobhar’, which means ‘foreign help’. This has a similar root to the Scots name Galbraith, which comes from the Scots Gaelic meaning ‘foreign Briton’ (which usually refers to early Welsh settlers in Scotland), and to the English name Gall (or Gaul) which is of Breton Gaelic origin and means simply ‘foreigner’.

The name Gallagher came mainly from Donegal and the eastern Ulster borderlands, where it was often one of the main family clans.

The name is highly popular in Ireland and is also amongst the top sixty names in Scotland. The Scottish popularity is due entirely to Irish immigration and does not stem from any native Gaelic derivation.

The name has been popular and widespread in Ireland since the fifteenth century. However, there are no references to this name in any early English records or rolls. The presumed reason for this is because the name did not appear in England in large numbers, or with its holder having sufficient status, until the major immigrations during the nineteenth century.

Because Gaelic and English do not run parallel in a strictly literal sense, the transliteration of the original O’Gallichobhair into English has resulted in a wide variety of different spellings. This is frequently the case with Gaelic names, though the twenty-three variants of Gallagher would seem to be exceptional. The main variations in the anglicized Gallagher are Gallacher and Gallaher, though some variations even begin with ‘Gol-’.

Saint Gall (c.550—645) and twelve disciples established a monastery at the source of the Steinach from which the famous monastery, present Swiss town and canton all take their names.

‘Gallagher’s Frolics’ is a traditional Irish jig.

The Gallaher Ulster Golf Championship is sponsored by the cigarette firm. For professionals and selected amateurs, this stroke-play tourney is played every August at the Shandon Park course outside Belfast. The prize money is over £4,000, making it Ulster’s major golfing event.

The cooperative retail movement in Ireland was founded by one Patrick Gallagher (1873—1964).

There are no towns, cities or major geographic features which are Gallagher-related.

In England, Scotland and Wales Gallagher is not common enough to be counted separately. In Ireland with about 23,000 namesakes Gallagher is the 14th most popular surname. Around the world Gallaghers are most common in Canberra (one in 1,045 families), Sydney (one in 2,541) and Auckland (one in 3,091). In the United States there are an estimated 77,000 Gallaghers. This makes it the country’s 362nd most popular surname.