Nikos Zachariadis (Greek: Νίκος Ζαχαριάδης; 27 April 1903 – 1 August 1973) was General Secretary of the Communist Party of Greece (KKE) from 1931 to 1956.

From prison, he lent his political influence to a united antifascist front following Italy's invasion of Greece on October 28, 1940.

Along with Markos Vafiadis, Zachariadis was an integral figure in the formation and operations of the KKE-led Democratic Army of Greece (DSE) during the Greek Civil War of 1946–1949.

Following the collapse of the military effort in 1949, Zachariadis and other leaders of the DSE retreated to Tashkent, capital city of Uzbekestan SSR.

Zachariadis fell out of favor with the Tashkent branch of KKE in 1955 and, following some infighting, he was removed from his post — ostensibly with the support and approval of Nikita Khrushchev — by May 1956.

Zachariadis spent the rest of his life in exile in Siberia, initially in Yakutia and later in Surgut, where — according to official KGB records — he committed suicide in 1973.

His father, Panagiotis Zachariadis, was of petty-bourgeois origin and worked as an expert in the Regie Company, a French firm possessing the tobacco monopoly in Turkey.

In the years until 1936, Zachariadis was a successful leader of the KKE by tripling the number of its members, gaining seats in the Greek Parliament and even acquiring control of some labour unions.

[2] Zachariadis's letter remains a cornerstone of the KKE's vital contribution to the National Resistance movement against the Fascist occupiers (1941–1944).

In May 1956, during the Sixth Plenum of the Central Committee of the KKE, the Soviet Communist Party intervened to expel Zachariadis from his post of General Secretary.

[7] On the base of documents, declassified from the archives of the Russian Ministry of Internal Affairs, it has been confirmed that Zachariadis committed suicide.

[8] In December 1991, just a few days after the fall of the Soviet Union, Zachariadis' remains were returned to his homeland of Greece, and he was given a funeral, which gave his supporters the opportunity to honour him.