The study, followed the health and development of 14,000 children born in 1991 and 1992, and examined their activity levels at the age of 11.
The analysis found that children born in spring were the least active, moving about nine per cent less.
"It's a modest difference, but interesting," BMJ quoted Mattocks, as saying.
"Children born in the autumn tend to be the most developed in their school year, so they are more likely to do better in sport, Mattocks said.
"Later-born children may struggle to keep up, and so may get 'turned off' exercise," Mattocks added.
The study is published in the British Medical Journal.