Following the outbreak of the First World War, Pope volunteered for the Australian Imperial Force (AIF) and was given command of the 16th Battalion. He took part in the Landing at Anzac Cove late in the day on 25 April 1915 and secured a gap in the defences at a feature that would soon be known as Pope's Hill. He continued to lead his battalion over the next months, including through the Battle for Baby 700 and Battle of Sari Bair. In October 1915, he briefly commanded the 4th Brigade before being evacuated sick later that month. By this stage of the campaign he had been mentioned in despatches and appointed a Companion of the Order of the Bath.