But that's not just an opinion floating around pubs and playgrounds across England.
Oh no, it's a fact.
UK betting firm Ladbrokes are saying that nothing in the entire history of sport even comes close to Claudio Ranieri's Foxes.
After all, Leicester City were a whopping 5000/1 to win the Premier League at the start of the season after only just maintaining their top flight status last term.
To go on and win it all this season would be easily the greatest sporting shock of all time - at least on paper.
A Ladbrokes spokesman said: "We've trawled through our archives and we can't find anything that even comes close to this.
"Leicester started the season 5000/1 to win the Premier League.
"Nothing like this has ever been seen in sports betting before.
"Japan beating South Africa in the Rugby World Cup was only 50/1.
"Greece to win Euro 2004 was one of the biggest shocks in football ... Even that was only 250/1.
"There have been some real longshot winners of the Grand National in recent years too, which at 100/1 are incredible, but nowhere near this Leicester side's achievement.
"What they've done is simply one of the most ridiculous, yet brilliant, things in sporting history ... Something we may never see again."
SOME OF THE WORLD'S GREATEST SPORTING SHOCKS
Buster Douglas beats Mike Tyson in 1990 - 33/1
Japan beating South Africa in the 2015 Rugby World Cup - 50/1
Aurora's Encore & Mon Mome - 100/1 Grand National winners
Greece at Euro 2004 - 250/1