Thanasis Hatzis (Amyndeo, 1905 - Athens, 16 November 1982) was a leading figure in the KKE and EAM, a resistance fighter and a fighter of the DSE.

Thanasis Hatzis was born in 1905 in Amyndeo, Florina. His family, agricultural and relatively wealthy, was devoted to the Macedonian Struggle in those years to defend the Greek populations from Bulgarian nationalist action. As a result of its exposure to the eyes of the Ottoman authorities, it was persecuted by the Turks and found itself poor in Thessaloniki.

Hatzis finished high school in Thessaloniki where he came into contact with socialist ideas. He became a member of the KKE and then went to Athens to study at the School of Dentistry. He emerged as a youth leader in the great student strikes of 1929-30. Subsequently, as a professional member of the KKE, he worked in organizations in Athens, Piraeus and the province.

For his revolutionary activities, he was imprisoned and during the Metaxian Dictatorship he was sent to Akronafplia. He escaped at the beginning of the Occupation and worked for the organizational revival of the KKE. He joined the EAM from its founding and was later elected general secretary of the EAM Central Committee. He maintained this position until August 1944, when he disagreed with the Treaty of Lebanon and was replaced by Partsalidis.

Hatzis took part in the December Uprising and was then sent as a KKE official in Central Greece and then to Thessaloniki, where he became secretary of the Communist Organization of Macedonia-Thrace. In the summer of 1946 he was arrested and exiled to Ikaria along with other Left-wing cadres. In 1947 he escaped from Ikaria and joined the Democratic Army of Greece (DSE). At the 5th Plenary Session of the Central Committee of the KKE, in December 1948, he disagreed with the party leadership and was removed from the Central Committee.

After the Civil War he settled as a political refugee in the Soviet Union, where he fell out with Zachariadis and was expelled from the KKE. After the dismissal of Zachariadis in 1956, he returned to the party, only to be expelled again at the 8th Plenary Session of the Central Committee of the KKE (1958). He repatriated to Greece in 1974 and died in Athens on 16 November 1982. He was buried at the First Cemetery of Athens on 18 November. He wrote the four-volume work The Victorious Revolution That Was Lost.