George II (Greek: Γεώργιος Βʹ, Βασιλεὺς τῶν Ἑλλήνων, Geórgios Βʹ, Vasiléfs ton Ellínon) reigned as King of Greece from 1922 to 1924 and from 1935 to 1947.
After a coup deposed King Constantine during the First World War, Crown Prince George, by then a Major, followed his father into exile in 1917. George's younger brother, Alexander, was installed as king by prime minister Eleftherios Venizelos, an avowed Republican.
When Alexander I died following an infection from a monkey bite in 1920, Venizelos was voted out of office, and a plebiscite restored Constantine to the throne. Crown Prince George served as a colonel, and later a major general in the war against Turkey. During this time he married his second cousin, on 27 February 1921 in Bucharest, Princess Elisabeth of Romania, daughter of King Ferdinand and Queen Marie of Romania. When the Turks defeated Greece at the Battle of Dumlupınar, the military forced the abdication of Constantine, and George succeeded to the Greek throne on 27 September 1922.
Following a failed royalist coup in October 1923, the Revolutionary Committee asked him to depart Greece while the National Assembly considered the question of the future form of government. He complied and, although he refused to abdicate, he left on 19 December 1923 for exile in his wife's home nation of Romania. When a republic was proclaimed on 25 March 1924, he was officially deposed and stripped of his Greek nationality, and his property was confiscated.
In Greece between 1924 and 1935 there were 23 changes of government, a dictatorship, and 13 coups. General Georgios Kondylis, a former Venizelist who had suddenly decided to throw in his lot with the monarchist forces, overthrew the government in October 1935 and appointed himself Prime Minister. He then arranged a plebiscite both to approve his government and to bring an end to the republic. On 3 November 1935, almost 98% of the reported votes supported restoration of the monarchy. George returned to Greek soil on November 25.
He died of arteriosclerosis on 1 April 1947, after he was discovered unconscious in his room at the Royal Palace in Athens.
King George II was styled "Βασιλεύς τῶν Ἑλλήνων" (King of the Hellenes).