The May Bumps 2003 were a set of rowing races held at Cambridge University from Wednesday 11 until Saturday 14 June 2003. The event was run as a bumps race and have been held annually in mid-June since 1887. See May Bumps for the format of the races. In 2003, a total of 169 crews took part (100 men's crews and 69 women's crews), with around 1500 participants in total.
Caius men rowed-over in 1st position, retaining the headship and holding it for the 5th time since 1998.
Newnham women bumped Jesus, Caius and Emmanuel to take their first Mays headship since 1976.
The highest men's 2nd VIII at the end of the week was Caius II, who bumped Downing II on the 1st day.