Academy graduate Maris spent the majority of the 2014/15 season playing Under-21 football but also featured out on loan at Nuneaton Town, and tasted first-team action with his debut at Bradford City's Valley Parade in late April.
On the final game of the season, the 19-year-old started against Rochdale - his full debut - as the Reds crushed the Dale 5-0.
Speaking to barnsleyfc.co.uk after penning his new deal, Maris said, "It feels good. It's what I've always wanted to do and to get another year's fantastic.
"Being at Nuneaton helped, so I wasn't as nervous on my debut, as I was used to first-team football.
"(Lee Johnson) He just said before the few games that he'd try me out. He said I'd done well at Nuneaton and had done well in training and deserved a chance."
