Maguire, 20, made his debut for the club as a 17-year-old substitute alongside Collins, 30, against Cardiff in 2011 and the central defensive partnership reached the 100-landmark in the derby defeat at Rotherham.
"He's probably the person I've played alongside most with during my career and I've certainly enjoyed the fruits of that partnership, with a lot of clean sheets that we kept last season," Collins told the club's official website.
"I'm sure this season we'll go from strength to strength. It's a pleasure to play with him. He's a good player and I'm Harry's biggest fan.
"People look at the size of him, the strength of him and forget how young he is. You look at the 100-odd games he's played and you really could count on one hand the bad performances he's put in.
"And that's bad by his standards, not by other people's standards - that's fantastic consistency for a young lad and if he keeps improving like he is doing he's got a lot of good years ahead of him."
- Sports & Recreation