The prime minister of the Hellenic Republic (Greek: Πρωθυπουργός της Ελληνικής Δημοκρατίας, romanized: Prothypourgós tis Ellinikís Dimokratías), usually referred to as the prime minister of Greece (Πρωθυπουργός της Ελλάδας, Prothypourgós tis Elládas), is the head of government of the Hellenic Republic and the leader of the Greek Cabinet.

According to Article 37 of the Greek Constitution, the president of the Hellenic Republic shall appoint the leader of the political party with the absolute majority of seats in the parliament as prime minister.

In 2015 Alexis Tsipras, a self-proclaimed atheist, became the first prime minister to opt for a secular affirmation instead of the traditional religious oath.

When Tsipras assumed the premiership again, on 21 September 2015, President Prokopis Pavlopoulos decided that the affirmation had to be more formal, as it follows: I affirm, on my honour and conscience, that I will follow the Constitution and the laws and will serve the general interest of the Greek People.The Maximos Mansion (Greek: Μέγαρο Μαξίμου) has been the official seat of the prime minister of Greece since 1982.

During the Greek War of Independence, different regions of Greece that were free of Ottoman control began establishing democratic systems for self-government, such as the Peloponnesian Senate.

In 1832, Greece's nascent experiment with democracy was ended and a monarchy was established with the underage Bavarian Prince Otto as king.

[6] King Otto's reign as an absolute monarch ended when agitators for a constitution (as promised when the monarchy was established) rose in the 3 September Revolution in 1843.

Otto was forced to grant a constitution and Andreas Metaxas took power; he is credited with being the first Greek to formally serve as "Prime Minister."

However, two factors maintained significant power for the crown: the Greek party structure was weak and client-based, and the monarch was free to select any member of parliament to form a government.

Moreover, article 31 stated that the king hires and fires ministers (Greek: Ο βασιλεύς διορίζει και παύει τους υπουργούς αυτού).

[17] The king, acting within his constitutional rights, tried to bring members of the Center Union party to his side and form a government, leading to Apostasia of 1965.

[18] The prolonged political instability between the politicians and the king in finding a solution led a group of Colonels to intervene and rule Greece for seven years.

In the meantime, the functions of the king were to be discharged by the incumbent President of the Republic General Phaedon Gizikis who was appointed by the Ioannides' short-lived regime as a nominal figurehead.

[19][20] The presidential powers, which overall exceeded those of the monarch under the 1952 Constitution, were drawn inspiration from the recent Gaullism reforms in the France where Karamanlis spent time (1963-1974).