The 26-year-old impressed at both ends of the pitch, providing three goals and contributing to four successive clean sheets to his side's promotion charge.
"Chey has been brilliant all season for us and has formed a great direct partnership with Dan Burn in the centre of defence," Wigan manager Paul Cook told the EFL website.
"It's a massive squad effort, though, and Chey would be the first to acknowledge the contributions of his teammates towards this award."
Dunkley, meanwhile, said of his award: "Throughout the season, we've always tried to have a strong foundation, which gives us the best chance of winning games.
"We go into the game looking to keep clean sheets and hopefully we've got the quality up there to score a goal to take us over the line.
"I like to say I'm aggressive in the air and like to get my head on things. I wouldn't say I was always working on the offensive side of the game but I do fancy myself to get goals here and there and chip in from defense."