Centre-half Rowley, 18, skippered the Saddlers’ youth team last season and is now looking to make the step-up into the first-team squad.
“I’m delighted that all the hard work over the past two years has resulted in this,” he told the club website.
“It’s great to finally sign my first professional contract but the real work begins now.
“It will be good to be part of the first-team group and I can’t wait for pre-season training to get under way.
“I’ll be looking to make a positive initial impression and show the coaching staff what I can do when I’m called upon.”
Fellow defender Matt Preston, 20, signed a one-year contract with the Saddlers on Monday.