The player, however, said he picked the Juventus star ahead of Messi while growing up.
Barcelona icon, Messi scored two goals during their 3-0 win at home to Manchester United to qualify for the Champions League semi-final.
Portugal captain, Ronaldo crashed out of the Champions League with Juventus after losing 2-1 to Ajax on Tuesday.
The Portugal legend netted his sixth goal of the competition in the game.
31-year-old Messi and Ronaldo, 34, have won the Ballon d’Or five times each since Ronaldo first won the award in 2007.
With both players ageing, some are looking at who will be the next superstar in the sport, with 20-year-old Mbappe, being touted for that status.
But when asked who he’d rather have in his team, Mbappe told France Football, “If I had the choice between Messi and Ronaldo for my team? I’d retire and take both of them, to be sure that we win!
“I could choose one, but it would likely be at the expense of the other. And you don’t have the right to denigrate one of these two monsters. To choose one would be an insult to everything that the other has achieved.
“When I was younger, I had fun comparing them both. From one year to the next, I changed [who he preferred], even though I admit to having defended Ronaldo more often.
“But now I’m grown up I’m less certain. There are the Barca followers who prefer [Johan] Cruyff and Messi. And there are others who will say that Ronaldo is the greatest athlete that football has known and has won things wherever he went.”
