A group of mid-level Greek Army officers launches the Goudi coup, seeking wide-ranging reforms.

The Goudi coup (Greek: ) was a military coup d'tat that took place in Greece on the night of 28 August [O.S. 15 August] 1909, starting at the barracks in Goudi, a neighbourhood on the eastern outskirts of Athens. The coup was a pivotal event in modern Greek history, as it led to the arrival of Eleftherios Venizelos in Greece and his eventual appointment as Prime Minister. At one stroke, this put an end to the old political system, and ushered in a new period. Henceforth and for several decades, Greek political life would be dominated by two opposing forces: liberal, republican Venizelism and conservative, monarchist anti-Venizelism.

The coup itself was the result of simmering tensions in Greek society, which reeled under the effects of the disastrous Greco-Turkish War of 1897, financial troubles, a lack of necessary reforms and disillusionment with the established political system. Emulating the Young Turks, several junior Army officers founded a secret society, the Military League. With Colonel Nikolaos Zorbas as their figurehead, on the night of 15 August, the Military League, having gathered together its troops in the Goudi barracks, issued a pronunciamiento to the government demanding an immediate turnaround for the country and its armed forces.

King George I gave in and replaced Prime Minister Dimitrios Rallis with Kyriakoulis Mavromichalis, without however satisfying the insurgents, who resorted to a large public demonstration the following month. When a stalemate was reached, the coup leaders appealed to a new and providential figure, the Cretan Eleftherios Venizelos, who respected democratic norms in calling for new elections. After his allies' twin victories in the Hellenic Parliament in August and November 1910, Venizelos became Prime Minister and proceeded with the reforms demanded by the coup's instigators.

The Hellenic Army (Greek: Ελληνικός Στρατός, romanized: Ellinikós Stratós, sometimes abbreviated as ΕΣ), formed in 1828, is the land force of Greece. The term Hellenic is the endogenous synonym for Greek. The Hellenic Army is the largest of the three branches of the Hellenic Armed Forces, also constituted by the Hellenic Air Force (HAF) and the Hellenic Navy (HN). The army is commanded by the chief of the Hellenic Army General Staff (HAGS), which in turn is under the command of Hellenic National Defence General Staff (HNDGS).

The motto of the Hellenic Army is Ἐλεύθερον τὸ Εὔψυχον ('Freedom stems from valour'), from Thucydides's History of the Peloponnesian War (2.43.4), a remembrance of the ancient warriors that defended Greek lands in old times. The Hellenic Army Emblem is the two-headed eagle with a Greek Cross escutcheon in the centre.

The Hellenic Army is also the main contributor to, and "lead nation" of, the Balkan Battle Group, a combined-arms rapid-response force under the EU Battlegroup structure.