- January 1: During the Greek War of Independence, the First National Assembly decides upon a constitution. The colours of the Greek flag are to be blue and white.
- January 5: Elias Mavromichalis lands in Aliveri with 600 Maniates to aid the cause of the Greek Revolution on the island of Euboea.
- January 14: Kamil Bey surrenders Acrocorinth to Theodoros Kolokotronis and the Greek revolutionaries.
- January 15: The First National Assembly of Independence at Epidaurus concludes its work.
- January 17: Ali Pasha is beheaded by the Turks on a small island of Lake Pamvotis. The severed head is sent to Sultan Mahmud II in Istanbul.
- February 20: During the Greek War of Independence, a Greek flotilla under Andreas Miaoulis defeats a Turkish one under Karapepe Ali at Patra Bay.
- February 23: The head of Ali Pasha - slain on January 17 - reaches Constantinople where Sultan Mahmud II puts it on display in front of his palace.
- February 25: The Revolutionary government of Greece outlaws slavery.
- March 9: Greek revolutionaries, under Theodoros Kolokotronis, defeat the Turkish army at Saravali, Achaea
- March 31: The massacre of Chios takes place during the Greek War of Independence. An estimated 100,000 persons are killed or sold into slavery.
- July 3: The Battle of Komboti is fought during the Greek War of Independence.
- July 4: The Battle of Peta is fought during the Greek War of Independence.
- July 12: Dramali Pasha begins the siege of the acropolis of Argos.
- July 26: The Battle of Dervenakia takes place.
- July 28: The remnants of Dramali Pasha's army are destroyed by Nikitaras at Klisoura.
- October 14: Kutahye pasha enters Vrachori and burns it to the ground.
- October 24: The first siege of Mesolonghi begins as Kutahye pasha's army encircle the city.
- December 14: The Holy Alliance denounces the Greek Revolution, considering it audacious and clumsy.
- December 31: Omer Vrioni and Kutahye end the first siege of Mesolonghi