Lions will also play Luton Town and Gillingham
Millwall will face West Bromwich Albion, Luton Town and Gillingham in the EFL Southern Group H following the conclusion of Wednesday morning's Group Stage draw.
The structure of the competition this season has been radically changed with the initial stages consisting of 16 groups of four teams which are regionalised with each group featuring an invited club and at least one team from League One and Two.
The invited club, in Millwall's case West Brom, will play one game at home and this will be at the first team ground of the chosen team. Each team meanwhile will play each other once either home or away.
In the group stages, clubs will be awarded three points for a win and one point for a draw. In the event of a drawn game however, a penalty shootout will be held with the victors gaining an extra point.
The top two placed teams in the group will progress to the knockout rounds.
Round Two will remain regionalised with the group winners at home against a second placed team from another group.
Round Three (16 teams) and Round Four (8 teams) will be free draws.
If any game is level after 90 minutes, the result will be determined by penalties.
Semi-Final and Finals
All semi-final clashes will be knock-out games and played at the stadium of the team drawn first. The final, meanwhile, will be played at Wembley Stadium in April 2017.
Key Dates for EFL Trophy Fixtures
w/c August 29, 2016 | Millwall v West Bromwich Albion
w/c October 3, 2016 | Millwall v Gillingham
w/c November 7, 2016 | Luton Town v Millwall
w/c December 5, 2016
w/c January 9, 2017
w/c January 23, 2017
w/c February 20, 2017