Dixon, 20, has scored five tries and kicked a goal so far this Super League campaign.
He said: “I’m really happy to get another few years at the Broncos. Everything has gone really fast, it seems like just a few hours since I was making my debut against St Helens and playing the majority of the season. To be where I am now is just a massive achievement.”
Head coach Tony Rea added: “People can see everything he does on the field. He contributes well and the really pleasing thing is he contributes off the field.
“He’s a really important person and he’s a pleasure to have around the place. He represent the club and everything we’re about by the way he represents himself. It’s a reward for what he does off the field complemented by what he does on the field.”