A pub session (seisiún in Irish Gaelic; seshoon in Manx Gaelic) refers to playing music and/or singing in the relaxed social setting of a local pub, in which the music-making is intermingled with the consumption of ale, stout, and beer and conversation. Performers sing and play traditional songs and tunes from the Irish, English, Scottish and Manx traditions, using instruments such as the fiddle, accordion, concertina, flute, tin whistle, uilleann pipes, tenor banjo, guitar, and bodhrán.
Singing and drinking have happened together from ancient times, but written evidence is fragmentary until the 16th century. In Shakespeare's Henry IV, Hal and Falstaff discuss drinking and playing the "tongs and the bones". There are good depictions of pub singing in paintings by Teniers (1610–1690) and Brouwer (1605/6-1638) but the best ones are by Jan Steen (1625/5-1656).
The 1830 Beer Act abolished the levy on beer and quickly doubled the number of pubs in England. The number peaked in the 1870s and declined after 1900. By the 1850s, an increasing number of student songs and commercial song-books were published across Europe. The most famous was the Scottish Students' Song Book by John Stuart Blackie (1809–1895). The mixture of traditional songs with hints of erotic humour continues to this day. The Irish tradition also benefited from the compilation of O'Neill's Music of Ireland, a compilation of 1,850 pieces of Irish session and dance music, published initially by Francis O'Neill (1848–1936) in 1903.
One of the most popular drinking songs, "Little Brown Jug," dates from the 1860s. By 1908 Percy Grainger had begun to record folk singers, but not in their natural habitat—the pub. In 1938 A.L. Lloyd persuaded his employers at the BBC to record the singers in the Eel's Foot pub in Eastbridge, Suffolk.