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.

The president of this council, Count Josef Ludwig von Armansperg was the de facto head of government under Otto.

[7] King Otto's reign as an absolute monarch came to an end when agitators for a constitution (as had been promised when the monarchy was established) rose up 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.