Researchers from the University of Queensland Diamantina Institute and the UK's Bristol University studied 5000 children aged seven-and-a-half years and examined whether BMI has a causal effect on asthma.
The study found the relative risk of asthma increased by 55 per cent for every extra unit of body mass index (BMI).
Asthma – a condition caused by inflammation of the airways - affects more than one in nine children in Australia, according to Asthma Australia.
Simon Bowler, Asthma Australia's medical spokesperson said the research should encourage parents and children to maintain a healthy weight to prevent childhood asthma.
"A cure for asthma is a long way off but this large study highlights preventative health strategies such maintaining a healthy BMI is a marker to be considered by parents and health professionals in treating asthma and potentially preventing the onset of such," he said.