Manager Kenny Jackett has agreed a new three-year contract with League One club Millwall.
The Lions reached the play-off final this season, but missed out on promotion as they were beaten 3-2 at Wembley by Scunthorpe United.
Jackett told the club's official website: "I'm pleased to commit myself to the next stage of Millwall's development and to build on the great strides we have made both on and off the field.
"As a group of players, management and staff, we are hungry to prove ourselves in the coming season with consistent quality performances.
Chairman John Berylson added: "The progress we have made in 18 months under Kenny has been tremendous.
"He has taken us from the brink of relegation to the verge of promotion in that short period of time and I am convinced the best is yet to come."