They can both be used to mean 'bravo' or 'well done', especially if someone has done something that shows skill, courage, or ingenuity. I'm not sure they are always used in the same way, though. For example, if someone has been brave enough to challenge her boss at work, you might say 'Good on her'. 'Good for you' can also be mean when someone has simply been lucky. For example, if someone has won a lottery, you might say 'Good for him'. I'm from the UK. Neither of these strike me as particularly British phrases, although both are used. 'Good on you' sounds Australian to me, for some reason.

when we use Both phrase as interjection .They have same meaning which is ( Well done; an exclamation of encouragement or congratulation.) You got married? Good on you! or you got married? Good for you! Good for you as adjective :meaning (Healty) Eating Fruit is good for you.

That's interesting! Here in the Washington DC area, I've never heard "good on you" "Good for you" is common, and has the meaning Waqas described

(New England) Well done; an exclamation of encouragement or congratulation. You got married? Good on you!

Thank you for your comments guys! I'm pretty sure that Aussies and Kiwis say "Good on you" and that's the same meaning as "well done". I think sometimes they use "Good on you" instead of saying "Thank you", but I'm not really sure... I might be wrong.