Fallon is an Irish surname from the Gaelic Ó Fallamhain, which comes from follamhnas and means "leader" or "ruler". It became a girls' name in the United States through the character Fallon Carrington on the 1980s soap opera Dynasty, and late-night host Jimmy Fallon has kept it familiar. Fallon entered the US top 1000 in 2019, peaked at number 688 in 2023 and ranks number 779 in 2025.