The Gallipoli Campaign, also known as the Dardanelles Campaign or the Battle of Gallipol took place at the peninsula of Gallipoli in the Ottoman Empire (in modern day Turkey) between 25 April 1915 and 9 January 1916, during the First World War. A joint British and French operation was mounted to capture the Ottoman capital of Constantinople and secure a sea route to Russia. The attempt failed, with heavy casualties on both sides.

The Gallipoli campaign resonated profoundly among all nations involved. In Turkey, the battle is perceived as a defining moment in the history of the Turkish people—a final surge in the defence of the motherland as the aging Ottoman Empire was crumbling. The struggle laid the grounds for the Turkish War of Independence and the foundation of the Republic of Turkey eight years later under Mustafa Kemal (Atatürk), himself a commander at Gallipoli.

The campaign was the first major battle undertaken by the Australian and New Zealand Army Corps (ANZAC), and is often considered to mark the birth of national consciousness in both of these countries. Anzac Day, 25 April, remains the most significant commemoration of military casualties and veterans in Australia and New Zealand, surpassing Armistic Day/Remembrance Day.