The visitors started the better of the two sides and took the lead though Keiran Agard midway through the first half.
But Town came back into the contest as the half went on and four minutes after the restart, they were level when Elliot Embleton's shot found the top corner.
The turnaround was complete when Wes Thomas struck from close range to make it 2-1, before Charles Vernam made sure of the win with a third goal.
Town
1 James McKeown
27 Luke Hendrie
12 Akin Famewo
24 Harry Davis
6 Danny Collins (C)
15 Harry Clifton
22 Elliot Embleton
7 Jake Hessenthaler
30 Ben Pringle
39 Wes Thomas
18 Charles Vernam
23 Sam Russell
19 Andrew Fox
2 Reece Hall-Johnson
11 Jordan Cook
4 John Welsh
16 Martyn Woolford
17 Harry Cardwell
MK Dons
1 Lee Nicholls
26 Baily Cargill
4 Joe Walsh
25 Callum Brittain
2 George Williams
3 Dean Lewington (C)
8 Alex Gilbey
24 Jordan Houghton
10 Chuks Aneke
14 Kieran Agard
32 Rhys Healey
Subs
22 Stuart Moore
12 Mitch Hancox
28 Oran Jackson
6 Ousseynou Cissé
20 Lawson D'Ath
7 Ryan Watson
19 Robbie Simpson
Attendance: 1,991 (154)