4. Arsenal | Fans: 598,000
Next up are Premier League side Arsenal, who are fourth on the list despite the fact they have not won a single trophy since 2005.
The Gunners have a large supporter base - and regularly sell out their home matches at the Emirates Stadium - so it's no surprise that they feature in this top five.
The £42m summer signing of Mesut Ozil probably boosted numbers a little, too.