"Billy Boys", also titled "The Billy Boys", is a loyalist song from Glasgow, sung to the tune of "Marching Through Georgia." It originated in the 1930s as the signature song of one of the Glasgow razor gangs led by Billy Fullerton and later became viewed to reflect the long running sectarian divide in the city. It is associated in particular with Rangers F.C..
Billy Boys originated in the 1920s as the signature tune of the Brigton Boys, also called The Billy Boys of Brigton Cross, who were a Protestant street gang in the Bridgeton area of Glasgow, led by Billy Fullerton. The gang often clashed with Catholic gangs such as the Norman Conks. Fullerton was a former member of the British Fascists who was awarded a medal for strike-breaking during the 1926 General Strike and formed a Glasgow branch of the British Union of Fascists with the onset of World War II. The song's geographic roots relate to Bridgeton Cross in Bridgeton, an area of Glasgow historically associated with the city's Protestant population, and with Scottish unionism. Brigton is the Scots form of Bridgeton. The Billy Boys song was often sung loudly when the gang performed it. They regularly sang it when they marched through primarily Catholic areas of Glasgow on Catholic holy days. This often led to the Brigton Boys being attacked by members of the Norman Conks as a result. Despite being primarily based in Glasgow, in the 1930s the Brigton Boys were invited to march in Belfast and sang Billy Boys while they were there as part of The Twelfth celebrations.