The Baggies boss beat off competition from Aidy Boothroyd of Watford, Charlton Athletic's Alan Pardew and Bristol City chief Gary Johnson to win the accolade after his side picked up 13 points from a possible 15 on offer.
Mowbray's side roared up to second place in the table on the back of their unbeaten run - which included a win over Scunthorpe at Glanford Park.
"We're on a journey this season and we've got targets and aims," said Mowbray.
"It's very early on in the season and we'll take each game as it comes and try and entertain as we go along.
"So far we've scored plenty of goals and our defence is much tighter - it's all about getting that balance right.
"The group of players we've got here are fantastic to work with. They look me right in the eye and want to learn and develop."
Leeds United boss Dennis Wise has been named League One manager of the month for the second successive time.
The Elland Road club have responded to their 15-point pre-campaign penalty for going into administration and are yet to be beaten in the league so far this season.
Barnet's Paul Fairclough has been handed his first ever manager of the month award in his third season as a Football League boss.
The Bees chief saw off the challenge of MK Dons' Paul Ince, Keith Hill of Rochdale and Paul Lambert from Wycombe Wanderers to claim the League Two accolade.