Spelling variations include: Baillie, Bailey, Bailie, Bayly, Bayley, Bailley, Baly, Ballye, Bayllie and many more.

First found in Northumberland where they were seated from very early times and were granted lands by Duke William of Normandy, their liege Lord, for their distinguished assistance at the Battle of Hastings in 1066 A.D.

Some of the first settlers of this name or some of its variants were: Mary Bailey, who was listed as being in Virginia in the year 1619, Jonas Bailey, who was recorded in Maine in 1634, James Baillou who settled in Georgia in 1733 with his wife and son, Elizabeth, Mathew, Matty, Stewart, William Bailie, who all arrived in Philadelphia in 1804. John, Joseph, Mathew, Robert, Samuel, Thomas, Walter, William Bailey, who arrived in Pennsylvania between 1770 and 1840. Several of the name came to Newfoundland. Among them were Richard Bayly, who settled in Bay de Verde in 1675, John, who arrived in Barrow Harbour in 1676.