Antill is best known for not stopping the futile charges on the Turkish lines at The Nek in the Gallipoli Campaign in August 1915, during which four waves of attackers barely got "over the top" before being cut down by Turkish fire. The ANZAC forces suffered a 60% casualty rate, most having been cut down "en masse" just feet from their own trenches. He later command the 3rd Light Horse Brigade in the final months of the Gallipoli Campaign, and then during the early part of the Sinai and Palestine campaign. In August 1916, he was offered command of the 2nd Infantry Brigade and commanded the brigade briefly on the Western Front, until his health deteriorated and he was evacuated to England in November 1916. In early 1917, Antill took over command of the embryonic 16th Infantry Brigade, but this formation was disbanded before it was fully formed and Antill ultimately did not see action again. He returned to Australia in late 1917.