The Blur guitarist called both reality talent shows "disgraceful", and added to The Independent that he believes that artists should "pay [their] dues" before becoming famous.
Coxon said: "To get better at anything you have to practise a lot. It doesn't just appear.
"I've only got myself to please. When I'm on my own in my front room with a guitar, there's no-one going to say to me, 'That's really great' if I play some old rubbish. I do believe in doing things right. Which is why The X Factor and The Voice are so disgraceful to me."
He added: "That's how I feel about it. Perhaps I'm old-fashioned in that sense - that I believe you have to pay your dues. Being a musician is not something you can become overnight."
The A + E singer-songwriter also expressed his wishes to follow his Blur bandmate Damon Albarn into more "adventurous" musical climbs, saying: "Damon's gone off to Mali and worked with all sorts of different people. Musically, he's put himself in some weird areas where he might have struggled.
"He's made some brave and adventurous moves and that's probably what I want to do."
Albarn recently denied reports that Blur and his other band Gorillaz are finished.
Graham Coxon was added last month to the NME/Radio 1 Stage lineup for the Reading and Leeds Festivals, along with Santigold and The Joy Formidable.
Watch the video for Graham Coxon's 'Ooh, Yeh Yeh' below: