"I feel that it is in the best interests of the club that I resign and give my successor the chance to turn things around with half the season left," Kinnear said in a statement on Forest's website.
"I was brought in last season to save the club from relegation, which I did, but feel the time is now right to give someone else a chance."
Forest are in the relegation zone of the Championship, one place and 2 points below City.
They visit Ninian park on Jan 3rd, ko 1:00pm.
