It is the first time in the history of the monthly award that a manager has won it four successive times.
Pep also landed the honour in September, October and November as his unbeaten side continue to receive praise from all corners.
City won seven and drew one of the eight domestic matches last month, with only Crystal Palace holding the Blues in the Premier League while a much-changed City side were beaten by Shakhtar.
The Blues scored 19 goals in December and bagged four on three different occasions and saw off Spurs, West Ham, Bournemouth, Newcastle, Swansea, Leicester and Manchester United.
Congratulations to Pep and his backroom staff on yet another award.