Grahl is a surname. Notable people with this surname include:
August Grahl (1791–1868), German portrait painter and miniaturist Denise Grahl (born 1993), German Paralympic swimmer Francisco Grahl (born 1992), Argentine footballer Jens Grahl (born 1988), German footballer John Grahl (born 1946), Scottish academic and professor John Grahl (comedian), Ghanaian comedian Steven Grahl, English cathedral organist Viola Grahl (born 1966), German field hockey player