William McKillop (1860 – 25 August 1909) was an Ayrshire-born grocer and restaurant-owner in Glasgow who became an Irish nationalist politician, serving for the last decade of his life as an Irish Parliamentary Party Member of Parliament (MP) for constituencies in Ireland. He was a founding member of the committee which established the Glasgow Celtic football club, but is probably better known for the William McKillop Cup, which he donated to Armagh Gaelic Athletic Association.
His father Daniel McKillop emigrated to Ayrshire from Glenarm in Antrim. William and his brother had moved to Glasgow, where in time they set up a licensed grocers, and were successful enough to buy out other businesses including the Royal Restaurant.
The by-now prosperous McKillop family were involved in several Irish political organisations in Glasgow. William's obituary in the Freeman's Journal described him as "a staunch Irish nationalist who took a lively interest in the Irish movement in Glasgow and was a leading member of the home Government Branch to which he always gave splendid financial support." In those days, Members of Parliament were not paid, and the Irish Party therefore had to find candidates wealthy enough to support themselves. William McKillop was asked to stand as the nationalist candidate for North Sligo at the 1900 general election, and readily agreed. He was elected unopposed and soon became Treasurer of the Irish Parliamentary Party.
For reasons that are unclear, McKillop switched seats at the 1906 general election, from North Sligo to South Armagh, where he was returned unopposed. He held the seat until his death on 6 August 1909.