Giorgos Efstathiou Sideris (Greek Γιώργος Σίδερης) was a Greek football defender.
Sideris was born on August 15, 1948 in Patra. He started his career at Proodeftiki Patra, moving on to Panachaiki.
Sideris played three times for the National Military team of Greece. He was a policeman by profession.