The landing at Anzac Cove on Sunday, 25 April 1915, also known as the landing at Gaba Tepe, and to the Turks as the Arburnu Battle, was part of the amphibious invasion of the Gallipoli Peninsula by the forces of the British Empire, which began the land phase of the Gallipoli Campaign of the First World War.

The assault troops, mostly from the Australian and New Zealand Army Corps (ANZAC), landed at night on the western (Aegean Sea) side of the peninsula. They were put ashore one mile (1.6 km) north of their intended landing beach. In the darkness, the assault formations became mixed up, but the troops gradually made their way inland, under increasing opposition from the Ottoman Turkish defenders. Not long after coming ashore, the ANZAC plans were discarded, and the companies and battalions were thrown into battle piecemeal and received mixed orders. Some advanced to their designated objectives, while others were diverted to other areas and ordered to dig in along defensive ridge lines.

Although they failed to achieve their objectives, by nightfall the ANZACs had formed a beachhead, albeit much smaller than intended. In some places, they were clinging onto cliff faces with no organised defence system. Their precarious position convinced both divisional commanders to ask for an evacuation, but after taking advice from the Royal Navy about how practicable that would be, the army commander decided they would stay. The exact number of the day's casualties is not known. The ANZACs had landed two divisions, but over two thousand of their men had been killed or wounded, together with at least a similar number of Turkish casualties.

Since 1916, the anniversary of the landings on 25 April has been commemorated as Anzac Day, becoming one of the most important commemorative dates for Australia and New Zealand. The anniversary is also commemorated in Turkey and the United Kingdom.

The Gallipoli campaign was a military campaign in the First World War that took place on the Gallipoli peninsula (Gelibolu in modern Turkey), from 17 February 1915 to 9 January 1916. The Entente powers, Britain, France and Russia, sought to weaken the Ottoman Empire, one of the Central Powers, by taking control of the Turkish straits. This would expose the Ottoman capital at Constantinople to bombardment by Allied battleships and cut it off from the Asian part of the empire. With Turkey defeated, the Suez canal would be safe, and a year-round Allied supply route could be opened through the Black Sea to warm water ports in Russia.

The attempt by the Allied fleet to force the Dardanelles in February 1915 failed and was followed by an amphibious landing on the Gallipoli peninsula in April 1915. In January 1916, after eight months' fighting, with approximately 250,000 casualties on each side, the land campaign was abandoned and the invasion force withdrawn. It was a costly campaign for the Entente powers and the Ottoman Empire, as well as for the sponsors of the expedition, especially the First Lord of the Admiralty (1911–1915), Winston Churchill. The campaign was considered a great Ottoman victory. In Turkey, it is regarded as a defining moment in the history of the state, a final surge in the defence of the motherland as the Ottoman Empire retreated. The struggle formed the basis for the Turkish War of Independence and the declaration of the Republic of Turkey eight years later, with Mustafa Kemal Atatürk, who rose to prominence as a commander at Gallipoli, as founder and president.

The campaign is often considered to be the beginning of Australian and New Zealand national consciousness; 25 April, the anniversary of the landings, is known as Anzac Day, the most significant commemoration of military casualties and veterans in the two countries, surpassing Remembrance Day (Armistice Day).