Middlesbrough have recorded to wins and two draws in September.
Chairman of the Manager of the Month judging panel, Alan Curbishley, said: “Middlesbrough have continued their great start to this season as Mowbray’s men remain unbeaten in the npower Championship.
“With Boro not conceding a single goal this month I am sure they will prove hard to beat this campaign.”
Middlesbrough skipper Matthew Bates has been named as npower Championship Player of the Month for September.
Mowbray said: “Matthew has played an integral role as captain and central defender in a team that has kept four clean sheets during September.
“Such an achievement is always a collective effort, of course, but Matthew has led by example and richly deserves this honour.”