Keelan is an anglicized form of the Irish Caolán, a diminutive of caol, "slender", so the name means "slender" or "little slender one". It is a close cousin of Kellan and Keegan and shares their easygoing Irish sound. In the United States Keelan ranked number 1205 in 2000, its best year of the century, stayed in the 1300s to 1800s through the late 2010s and has drifted to number 2463 in 2025 with 55 boys.