At the end of the year, the marks of the girls-only class were eight per cent higher than either of the other groups. The split, though, had no effect on the boys' only or mixed classes, the Independent reported.
The researchers have insisted that the findings could help determine policies regarding the way students are taught in future - both at university and in schools. It may lead to higher demands for single-sex teaching.
"I would like to see policy makers think about this," Patrick Nolen, who conducted the research with Alison Booth - both from the university's economics department, said.
"This finding is relevant to the policy debate on whether or not single-sex classes within co-ed schools could be a useful way forward," the study concluded.
The study has been published in the New Economic Journal.