Ireland striker Aiden O'Brien and under-21 skipper Jayson Molumby will remain with Millwall until the end of this season.
Both O'Brien and Molumby have signed contract extensions that means they will remain with the Championship club for the remainder of the current league campaign.
Molumby, who is predicted to make his first senior international appearances in the autumn, is currently on loan from Premier League club Brighton.
Danny McNamara, another Ireland under-21 international, will stay with the Lions until the end of the 2020/21 season.
The English-born full-back made his Ireland under-21 debut last November in the European Championship qualifier win in Armenia.
McNamara spent the first half of this term on loan at Newport County in League Two, but returned to Milwall at the start of the year to have groin surgery.
Meanwhile, Shane McLoughlin has signed a contract extension with Wimbledon until the end of the 2020/21 season.
The versatile McLoughlin joined the Dons from Ipswich in January of last year and has made 37 appearances for the League One club.
Dons boss Glyn Hodges had been keen on retaining McLoughlin and said: "I thought he was really good last season, so I’m looking forward to more of the same next season.
"He gets on with everyone, he’s a popular member of the squad, and we are looking forward to him kicking on".
