The legendary actor has appeared in many classic films spanning seven decades, including the likes of Lawrence of Arabia, Goodbye Mr Chips and My Favourite Year.
"It is time for me to chuck in the sponge," the 79-year-old said in a statement. "To retire from films and stage. The heart for it has gone out of me - it won't come back."
O'Toole holds the record for most amount of Oscar nominations for 'Best Actor' without a win, most recently for 2006's Venus.
Digital Spy takes a look back at just a few of the somehow-not-knighted actor's most famous roles.
In pictures - Peter O'Toole's career in pictures:
Copyright: Rex Features Everett Collection