Spicer, 30, joined the Rams in 2009 from York City Knights, and has played 138 games in Dewsbury colours.
“It’s always nice to be signed on. I’m very happy here and it was pleasing to know the club wanted to offer me a new contract,” he told the club’s official website.
“I didn’t hesitate in signing up for another year and I’m looking forward to seeing what the future holds for us as a team.
“It’s a great club. I’ve been here most of my career now and they’ve always been good to me and my family, so I’m delighted to be here for another year.
“There have been a lot of changes since I first signed, but one thing which has stayed the same has been the positive atmosphere around the club.
“Good morale seems to be one of the backbones of this club, which makes it a very enjoyable place to be.
“A lot of players have come and gone during my time at Dewsbury but we’ve always felt like a very close-knit family, which is something we’re very fortunate to have.”