The Dark Knight star was approached for the role of ageing ruler Odin in the 2011 blockbuster opposite Chris Hemsworth as the hammer-wielding hero.
However, Oldman has now revealed he snubbed the part and it went to Sir Anthony Hopkins instead.
He tells Britain's The Independent newspaper, "I don't want to be playing Thor's dad just yet. They asked me to do that one and I said 'No, I'm far too young for that.' I wasn't going to run around with the grey beard going 'Son, you will be cursed'... I'm still a bit too sprightly for that stuff."