Auchinleck saw active service in the First World War and was deployed with his regiment to defend the Suez Canal: in February 1915 he was in action against the Turks at Ismaïlia. His regiment moved into Aden to counter the Turkish threat there in July 1915. The 6th Indian Division, of which the 62nd Punjabis were a part, was landed at Basra on 31 December 1915 for the Mesopotamian campaign. In July 1916 Auchinleck was promoted acting major and made second in command of his battalion. He took part in a series of fruitless attacks on the Turks at the Battle of Hanna in January 1916 and was one of the few British officers in his regiment to survive these actions.