In the landing at Gallipoli on 25 April 1915, Denton was wounded in the leg. He remained on duty for some time before being evacuated, during which he helped to organise the transmission of information between the onshore artillery and the offshore naval support. Denton was mentioned in despatches for his actions, and later in the year was awarded the Distinguished Service Order (DSO), becoming the first officer of the 3rd Brigade to receive that honour. He was hospitalised on Malta from July 1915 to January 1916, when he rejoined the 11th Battalion as its second-in-command. After training in Egypt, the unit was moved on to the Western Front, arriving in France in April 1916. It was subsequently involved in the Battle of Pozières.