In terms of followers Net-A-Porter ranked second with over 41,000, while online retailer Asos came in third with only 35,000.
Topman’s sister store, Topshop, had only 30,000 followers in June. At the time of writing this had increased to 36,500.
Boden completes the top five with just 19,000 followers.
eMarketer also looked at the top brands on Facebook and Twitter.
Amazon dominated on Facebook with 3.8 million followers in June thanks to an increase in its use of Sponsored Stories and promoted links.
Topshop, previously the No.1 UK retailer in terms of Facebook followers, actually lost fans in the previous three months and now has 3.4 million.
However, on Twitter, Topshop comes out on top, with more than 600,000 followers while Amazon UK has only 78,000. Globally Amazon has just over 570,000 followers.
ASOS and Net-A-Porter ranked second and third, respectively.