The Royal National Mod, (Scottish Gaelic: Am Ṃd Nàiseanta Ŕoghail), is the annual national mod, a festival of Scottish Gaelic song, arts and culture. It was founded by and run by An Comunn Gaidhealach. St Columba's Church, Glasgow greatly influenced the Mod's inception when, in 1891, its choir was invited to give a Gaelic Concert in Oban, presided over by Lord Archibald Campbell. The concert was a huge success and was attended by most of the nobility, including Louise, Princess Royal and Duchess of Fife. After the Concert the Choir were entertained to supper at the Alexandra Hotel, and a description of the entertainment is given in one of William Black's novels. This concert was the prelude to the Gaelic Mod, the first being held at Oban the following year, when St. Columba Choir were successful in the Choir competition. It has been held most years in October since 1892 It is usually just called The Mod. The only years in which the National Mod was not held were the war years of 1914-1919 and 1939-1946. The "Royal" was not originally part of the name. It is still the practice of the St Columba's Church to send a Concert Party to start off the fund-raising when the Mod visits Oban. As well as winning the premier Choir competition for the first three years, the church has also had many Mod Gold Medallists including its present minister, the Reverend Donald Michael MacInnes, who took the premier award in 1990

The Mod largely takes the form of formal competitions. Choral events and traditional music including Gaelic song, fiddle, bagpipe, clarsach and folk groups dominate. Spoken word events include children and adult's poetry reading, storytelling and Bible reading, and categories such as Ancient Folk Tale or Humorous Monologue. Children can also present an original drama, and there are competitions in written literature. The Mod also runs an annual shinty competition, the Mod Cup, between the two shinty teams closest to the place where the Mod is taking place.

The winners of each day's competitions are invited to perform in the winners' ceilidhs held every evening.

The Mod draws a large crowd, which leads local venues to put on various events in addition to the official Mod events. These events are collectively referred to as The Mod Fringe, analogously to Edinburgh Festival Fringe which began as a group of independent artists performing in Edinburgh at the same time as the Edinburgh International Festival.

Culturally, the Mod is comparable to the Welsh Eisteddfod.

To participants, the Mod is also an opportunity to meet with old friends and make new ones. The Mod is popularly known as the "Whisky Olympics".

Scottish Gaelic may be more correctly known as Highland Gaelic to distinguish it from the now defunct dialects of Lowland Gaelic. Of these Galwegian Gaelic was spoken in Galloway and seems to have been the last dialect of Gaelic to have been spoken in Lowland Scotland, surviving until the Early Modern Period. By the end of the Middle Ages, Lowland Gaelic had been replaced by Middle English/Lowland Scots[citation needed] across much of Lowland Scotland, while the Brythonic language had disappeared. There is, however, no evidence of a linguistic border following the topographical north-south differences. Similarly, there is no evidence from placenames of significant linguistic differences between, for example, Argyll and Galloway. Dialects on both sides of the Straits of Moyle (the North Channel) linking Scottish Gaelic with Irish are now extinct.