The League Two club continued their giant-killing ways after their quarter-final triumph over Arsenal by recording a two-goal win which gives them a handy advantage heading to the second leg to be played at Villa Park on January 22.
Nahki Wells gave the Bantams the ascendency inside 20 minutes when he slotted home past Shay Given after a deflected shot had fallen to him inside the area and it only got better for Phil Parkinson's men when Rory McArdle headed home Gary Jones' leftwing cross with just over ten minutes remaining.
Villa pulled one back through Andreas Weimann in the 82nd minute who raced onto Darren Bent's flick-on but Bradford wrapped it up with two minutes left through Carl McHugh who rose above Christian Benteke to guide home Jones' corner.
Tomorrow night's semi-final sees Chelsea host Swansea City at Stamford Bridge prior to their return bout at the Liberty Stadium on January 23. The victors of both the Villa v Bradford and Swans v Blues ties will meet in the 2012/13 Capital One Cup final at Wembley Stadium on February 24.