London-listed MySale, which as of Wednesday's close had a market capitalisation of just 11 million pounds ($13.4 million), connects global buyers and sellers to Australian and New Zealand e-commerce sites.
Frasers, formally called Sports Direct, said its investment created an opportunity for a strategic partnership where its end of line products could be sold.
"This pipeline will be further enhanced by the benefits of counter seasonality between the European and Australian climates," it said.
Ashley has a history of taking strategic stakes in other retailers.
Last week, Frasers increased its maximum exposure to German fashion brand Hugo Boss to $937 million.
($1 = 0.8230 pounds)
(Reporting by James Davey. Editing by Jane Merriman)