The automotive brand will become official supplier to the England team and Wembley Stadium.
The marque is the latest partner under the FA’s new sponsorship structure following recent deals with Mars, McDonalds and Carlsberg.
However, the governing body is still looking for to secure a headline sponsor for the FA Cup after energy firm Eon announced last year that it would not be extending its partnership beyond this season.
It is also still locked in negotiations with England team sponsor Nationwide about extending the financial services brand’s current agreement after it expires in June but is also talking to other potential partners after the mutual’s right to exclusive negotiations expired.
The FA is understood to want £30m from the deal but Nationwide has only offered £20m. According to some reports, the FA is also talking to Hyundai and Blackberry.
The Fiat deal is expected to be the first of three suppliers to be unveiled over the next week.