The fixture will be played the week commencing January 9th 2017 at Huish Park.
Darren Way’s side progressed to the last 16 of the competition with an impressive 4-1 win over Sky Bet League One side MK Dons on Tuesday.
Southampton and Reading will play each other on Wednesday, December 21st to see who heads to Somerset in the New Year.
The draw took place live on Sky Sports News at 11.30am and was drawn by Phil Babb and Chris Iwelumo.
THIRD ROUND DRAW IN FULL
Mansfield Town v Walsall/Oldham
Luton Town v Chesterfield
Oxford United v Scunthorpe United
Blackpool v Wycombe Wanderers
Cheltenham Town/Leicester City U21 v Bradford City
Yeovil Town v Southampton U21/Reading U21
Coventry City v Brighton & Hove Albion U21
Swansea City U21 v Wolves U21