2003 Isle of Man TT

The 2003 Isle of Man TT was the 96th edition of the event. It was marred by the high-profile death of outright lap record holder and nine-time TT winner David Jefferies during practice. Jefferies crashed at around 180 mph at Crosby, due to a patch of oil that was not signalled by the marshals. In the aftermath of Jefferies' crash, Jim Moodie's neck was hit by the cables of a telegraph pole laid down by the accident, but he was not seriously injured. Friend and rival of Jefferies John McGuinness was one of the first riders on the scene, and described it to be "like a war zone".

Two riders took two wins during the event: Shaun Harris and Adrian Archibald. Shaun Harris won the Production 600 and 1000 races, the only two TT podiums of his career. Adrian Archibald took an emotional Formula One TT win, which he dedicated to his former team-mate David Jefferies, and then won the prestigious Senior TT.

Fog was a recurring issue during the final few days of the event, causing delays and shortened race distances for the Production 600 TT and Senior TT.