Josef Ferstl Sr., known as Sepp Ferstl, (born 6 April 1954) is a retired German World Cup alpine ski racer who won the Hahnenkamm, the world's most prestigious downhill race, in consecutive years (1978, 1979).
He made his World Cup debut at the race in 1974 at age 19, and won a silver medal at the World Championships in 1978 in the combined.
Born in Traunstein, Bavaria, he competed for West Germany at the Winter Olympics in 1976 and 1980, and is the father of German alpine racer Josef Ferstl Jr..