Millwall head to Preston North End on 23rd September before returning to The Den for a double-header against Reading and Barnsley.
The Lions will take on the Deepdale outfit in the League for the first time in six years, before Jaap Stam's side, who narrowly missed out on promotion to the Premier League via the Play-Offs, visit south London on the 26th.
A battle of the last two Sky Bet League One Play-Off Final winners will take place at The Den on 30th September as Neil Harris' team take on The Tykes, before the second London derby of the season will see Millwall travel west to Brentford on 14th October - after another international break.
Ahead of the new campaign, millwallfc.co.uk takes a look at all 23 of the club's Championship opponents, continuing with Preston North End, Reading, Barnsley and Brentford...
Preston North End
Stadium: Deepdale
Manager: Alex Neil
Sat Nav Post Code: PR1 6RU
Nearest Train Station: Preston
Last Meeting: Millwall 1-0 Preston North End - FA Cup Third Round - 5th January 2013
The Lions will meet North End for the 61st time on 23rd September. Millwall currently register 28 wins to Preston's 23.
Reading
Stadium: Madejski Stadium
Manager: Jaap Stam
Sat Nav Post Code: RG2 0FL
Nearest Train Station: Reading
Last Meeting: Millwall 0-0 Reading - Sky Bet Championship - 27th January 2015
The Lions have won 35 out of 97 ties against The Royals - Reading have 40 wins to their name, whilst 23 have been drawn.
Barnsley
Stadium: Oakwell
Manager: Paul Heckingbottom
Sat Nav Post Code: S71 1ET
Nearest Train Station: Barnsley
Last Meeting: Barnsley 3-1 Millwall - Sky Bet League One Play-Off Final - 29th May 2016
The Lions will look to avenge four straight defeats to The Tykes when the two clubs meet on 30th September - Millwall's last win came in November 2013.
Brentford
Stadium: Griffin Park
Manager: Dean Smith
Sat Nav Post Code: TW8 0NT
Nearest Train Station: Brentford
Last Meeting: Brentford 2-2 Millwall - Sky Bet Championship - 21st March 2015
Goals are assured in this particular London derby - there have been 20 in the last five games between the two. The Griffin Park meeting will be the 64th overall.