The Shrewsbury Town chief landed the award after a stunning run of results to turn Town’s dismal form on its head and go unbeaten in seven league games, lifting the side five points clear of the drop zone.
Cotterill claimed the award ahead of Blackpool’s Neil Critchley – who lost 1-0 at Shrewsbury in Salop’s last game – Karl Robinson, of Oxford, and Crewe’s David Artell.
Town took 15 points from a possible 21 with four wins, including three away at promotion-hunting sides, and three draws last month.
Among the judging panel was EFL Sky pundit Don Goodman, who said: “Things looked pretty bleak for Shrewsbury when Steve Cotterill took over, but their prospects look a whole lot brighter after a miraculous run of form over the month of December.
“Cotterill’s arrival produced 15 vital points, despite a horrid run of games on paper. The Shrews began playing for their new manager, and their new-found determination was clear as day. A superb period, headlined by three massive victories on the road.”
Former Barnsley, Bristol City and Sheffield Wednesday boss Danny Wilson, who chairs the judging panel, added: “It was a fantastic turnaround of results in December for Steve and his Shrewsbury team.
“They faced a set of really tough fixtures against teams around the top of the table and just outside the play-off places but returned with 15 points, only losing one game.”
Cotterill’s side have not been in action since the 1-0 victory at home to Blackpool in front of spectators two Tuesdays ago.
Last weekend’s clash at home to Crewe was postponed after two positive Covid-19 cases and a spate of further positive tests this week have resulted in tomorrow’s televised FA Cup third round tie at Premier League Southampton being postponed.