It was reported earlier this week that both Leicester and Southampton had seen bids that could rise as high as £24m accepted for the former Coventry playmaker.
However, the 'Foxes' appear to have beaten off the competition, with 'The Daily Mail' reporting that Maddison has opted for a move to the King Power.
The 21-year-old is reportedly set to sign a five-year deal with Claude Puel's side, taking their spending for the summer close to the £50m mark following the aquisitions of Jonny Evans and Ricardo Pereira.
The fee, thought to be £22m up front with £m in add-ons and a 10% sell-on clause, is set to smash the record total ever paid for a Championship player.
Maddison scored 15 goals in 47 appearances for Norwich last season and is currently recovering from a knee ligament injury suffered on the final day of the season, with the creative midfielder expected to return to full fitness next month.