The Battle of Gallipoli took place at Gallipoli peninsula in Turkey from 25 April 1915 to 9 January 1916, during the First World War. A joint British Empire, most notably the Australians, and French operation was mounted to capture the Ottoman capital of Constantinople (now Istanbul), and secure a sea route to Russia. The attempt failed, with heavy casualties on both sides.

In Turkey, the campaign is known as the Çanakkale Savaşları, after the province of Çanakkale. In the United Kingdom, it is called the Dardanelles Campaign or Gallipoli. In France it is called Les Dardanelles. In Australia, Official Histories New Zealand, The Gallipoli campaign | NZHistory and Newfoundland, Newfoundland Regiment: Gallipoli it is known as the Gallipoli Campaign or simply as Gallipoli.

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 defense of the motherland as the centuries-old Ottoman Empire was crumbling. The struggle laid the grounds for the Turkish War of Independence and the foundation of the Turkish Republic eight years later under Atatürk, himself a commander at Gallipoli.

In Australia and New Zealand, the campaign was the first major battle undertaken by a joint military formation, 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 (April 25) remains the most significant commemoration of military casualties and veterans in Australia and New Zealand, surpassing Armistice Day/Remembrance Day.