Garcia's Brighton went the entire month unbeaten, winning three and drawing one of their four matches, including a 3-0 win over Blackburn Rovers.
"I would like to dedicate the award to the fans, who have been so supportive since my first day at Brighton & Hove Albion, fill the stadium for every match and support us away from home," said Garcia.
"I'm very proud to receive the award on behalf of the club, and proud of the players and staff because they are the ones who deserve the award.
"This is an award for everyone, it's not an individual award, as it is ultimately the team's results in November which won the award.
"We have shown what we can do, with a great month of results and performances, the challenge now is to continue that going forward."
Former Charlton Athletic manager Alan Curbishley chairs the Sky Bet Manager of the Month judging panel and said: "Oscar is now making an impact at Brighton following his appointment over the summer.
"He fully deserves this award and will be hoping to extend Brighton's form as we approach the busy festive period."
Sky Sports' Football League pundit Don Goodman said: "Three victories took Brighton from 16th to ninth in the Sky Bet Championship in November.
"After a difficult October, Oscar has tightened the defence and got his team scoring much-needed goals."
Whites striker McCormack has been named the Sky Bet Championship Player of the Month after scoring seven goals in November, including all four in the 4-2 win away to Charlton.
Leeds United manager Brian McDermott said: "I'm delighted for Ross winning Player of the Month, quite rightly in my opinion, although I'm biased!
"He has started December well with two goals, and let's hope he can win it this month as well."
Goodman said: "McCormack's four goals at Charlton make him the stand-out player in the Sky Bet Championship this month and have put him in the hunt for the golden boot.
"The Scottish international is in fine form and Leeds will need to keep him firing for the rest of the season if they are to stay in play-off contention."