Derfel is a Welsh and German surname. In German, it is derived from "Der Fels" meaning "the rock". In Welsh, it is used as a first name as well, meaning "strong".[1] Notable people with this surname include:
- Robert Jones Derfel (1824-1905), a Welsh poet and political writer
- Saint Derfel, also known as Derfel Gadarn, a 6th-century Celtic monk