Lonhro resumed in the 2003 autumn winning in the Expressway S-Gr2 (1,200m) by 2 lengths. Three weeks later, he won the Apollo S-Gr2 (1,400m) by 3½ lengths with a further 2 lengths to third. He was back a week later in the Chipping Norton Stakes-Gr1 (1,600m) at Warwick Farm, coming away to win under hands and heels riding by 1½ lengths from Shogun Lodge. Next on the agenda was the George Ryder S-Gr1 (1,500m) at Rosehill where Lonhro again won easily, this time by a 2 length margin. He was the raging favourite for the Doncaster Handicap-Gr1 (1,600 m) at Randwick, where he carried topweight of 57.5 kg. Defier and Shogun Lodge looked to be his main dangers, but then the rain fell and both his rivals were scratched when the track was rated officially slow. Inside the final 200m, Grand Armee, carrying 6 kg less than Lonhro, hit the front and raced clear to pass the post three lengths ahead of Dash For Cash with two lengths to Boreale, who held out Lonhro for third. This was Lonhro's third and final unplaced run in a race.