Stan created some of the most famous superheroes, including Spider-Man, The Hulk, Fantastic Four, Iron Man, Thor and X-Men.
An attorney for Stan's daughter, Kirk Schneck, told CNN that he was taken by an ambulance from his Los Angeles home on Monday morning to Cedar's Sinai Medical Centre, where he then passed away.
His cause of death is not yet known.
Stan Lee's death comes less than a year and a half after his wife Joan Lee passed away in July 2017, at 93-years-old.
Rest in peace legend.