| Dates | Events | |
| August 8 – November 11 |
Hundred Days Offensive, last offensive on Western Front. |
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| August 13 – September 3 |
Battle of San Matteo. |
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| August 21 – September 3 |
Second Battle of the Somme (also known as the Third battle of the Somme), a phase of the Hundred Days Offensive. |
Details |
| August 21 – September 3 |
Second Battle of Bapaume, a phase of the Second Battle of the Somme. |
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| August 26 – September 3 |
Fourth Battle of Arras (also known as Second Battle of Arras (1918)), a phase of the Second Battle of the Somme |
Details |
| August 26 – September 14 |
Battle of Baku, last Turkish offensive of the war. |
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| August 31 – September 3 |
Battle of Mont Saint-Quentin, a phase of the Second Battle of the Somme. |
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| September 1–2 |
Battle of Peronne, a phase of the Battle of Mont Saint-Quentin. |
Details |
| September 2–3 |
Battle of Drocourt-Queant Line, final phase of the Second Battle of the Somme. |
Details |
| September 8-23 |
Ufa Conference: Formation of the Provisional All-Russian Government with the support of the Czechoslovak Legion. |
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| September 10 |
Battle of Savy-Dallon, a phase of the Hundred Days Offensive. |
Details |
| September 12 |
Battle of Havrincourt, a phase of the Hundred Days Offensive. |
Details |
| September 12–19 |
Battle of Saint-Mihiel, a phase of the Hundred Days Offensive. |
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| September 14 |
Battle of Vauxaillon, a phase of the Hundred Days Offensive. |
Details |
| September 14–29 |
Vardar Offensive, final offensive on the Balkan Front. |
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| September 15 |
The Allies (French and Serbs) break through the Bulgarian lines at Dobro Polje, a phase of the Vardar Offensive. |
Details |
| September 18 |
Battle of Epehy, a phase of the Hundred Days Offensive. |
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| September 18–19 |
Third Battle of Doiran, a phase of the Vardar Offensive, The Bulgarians halt the British and Greek advance. |
Details |
| September 18 – October 17 |
Battle of the Hindenburg Line, a phase of the Hundred Days Offensive. The Allies break through the German lines. |
Details |
| September 19–25 |
Battle of Megiddo. The British conquer Palestine. |
Details |
| Battle of Nablus, a phase of the Battle of Meggido. |
Details |
| Third Transjordan attack, a phase of the Battle of Nablus. |
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| Battle of Sharon, a phase of the Battle of Megiddo. |
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| September 22 |
The British capture Jisr ed Damieh in the Battle of Sharon. |
Details |
| September 25 |
The British capture Tiberias during the Battle of Sharon. |
Details |
| September 19 |
Battle of Tulkarm, a phase of the Battle of Sharon. |
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| Battle of Arara, a phase of the Battle of Sharon. |
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| September 19–20 |
Battle of Tabsor, a phase of the Battle of Sharon. |
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| September 20 |
Capture of Jenin, a phase of the Battle of Sharon. |
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| British capture both Afulah and Beisan during the Battle of Sharon. |
Details |
| September 20–21 |
Battle of Nazareth, a phase of the Battle of Sharon. |
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| September 23 |
Battle of Haifa, a phase of the Battle of Sharon. |
Details |
| September 25 |
Battle of Samakh, a phase of the Battle of Sharon. |
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| Second Battle of Amman, a phase of the Third Transjordan Attack. |
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| September 26 – November 11 |
Meuse-Argonne Offensive, the final phase of the Hundred Days Offensive and of World War I. |
Details |
| September 26 – October 1 |
The British enter Damascus. |
Details |
| September 26 |
Battle of Somme-Py (Initial phase of the Meuse-Argonne Offensive). |
Details |
| Charge at Irbid, a phase of the Capture of Damascus. |
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| September 26–27 |
British capture Deraa during the Capture of Damascus. |
Details |
| September 27 |
Battle of Jisr Benat Yakub, a phase of the Capture of Damascus. |
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| September 27 – October 1 |
Battle of the Canal du Nord, a phase of the Battle of the Hindenburg Line. |
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| September 28 – October 2 |
Fifth Battle of Ypres (also known as Advance on Flanders), a phase of the Battle of the Hindenburg Line. |
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| September 29 – October 10 |
Battle of St. Quentin Canal, a phase of the Hundred Days Offensive. |
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| September 30 |
Bulgaria signs an armistice with the Allies. |
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| Battle of Saint-Thierry (Initial phase of the Meuse-Argonne Offensive). |
Details |
| Charge at Kaukab, a phase of the Capture of Damascus. |
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| Charge at Kiswe, a phase of the Capture of Damascus. |
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