The Battle of Sari Bair (Turkish: Sarı Bayır Harekâtı), also known as the August Offensive (Ağustos Taarruzları), represented the final attempt made by the British in August 1915 to seize control of the Gallipoli peninsula from the Ottoman Empire during the First World War.

At the time of the battle, the Gallipoli Campaign had raged on two fronts – Anzac and Helles – for three months since the Allied land invasion of 25 April 1915. With the Anzac front locked in a tense stalemate, the Allies had attempted to carry the offensive on the Helles battlefield – at enormous cost and for little gain. In August, the British command proposed a new operation to reinvigorate the campaign by capturing the Sari Bair ridge, the high ground that dominated the middle of the Gallipoli peninsula above the Anzac landing.

The main operation started on 6 August with a fresh landing 5 miles (8.0 km) north of Anzac at Suvla Bay in conjunction with the Australian and New Zealand Army Corps. The Allies mounted an attack north into the rugged country alongside the Sari Bair range with the aim of capturing the high ground and linking with the Suvla landing. At Helles, the British and French were now to remain largely on the defensive.