Guillermo Gorostiza Paredes was a Spanish footballer who played as a forward.

Athletic Club, commonly known as just Athletic domestically and often as Athletic Bilbao abroad, is a professional football club based in the city of Bilbao in the Basque Country, Spain. They are known as Los Leones because their stadium was built near a church called San Mamés, which was named after Saint Mammes, an early Christian thrown to the lions by the Romans. Mammes pacified the lions and was later made a saint. The team plays its home matches at the San Mamés Stadium. Its home colours are red and white-striped shirts with black shorts.