Llewellyn ranked #10677 among U.S. baby names in 2024. Since 1880, 3,728 babies have been named Llewellyn, peaking in 1918 with 79 births. The 1920s were its biggest decade, with 638 births. Llewellyn is on the rise, up about 70% over the past five years. It is predominantly a boys' name.