| 25 Nov 13 | J. Marquis John Marquis |  MillwallMIL | → |  Torquay UnitedTQU | Loan |
| 19 Nov 13 | J. Wright Josh Wright | MillwallMIL | → |  Leyton OrientLEY | Loan |
| 14 Nov 13 | G. Moussi Guy Moussi |  Nottingham ForestFOR | → | MillwallMIL | Loan |
| 05 Nov 13 | J. Hoyte Justin Hoyte |  MiddlesbroughMID | → | MillwallMIL | Loan |
| 31 Oct 13 | K. Osborne Karleigh Osborne | MillwallMIL | → |  Bristol CityBRC | Loan |
| 01 Oct 13 | J. Henry James Henry | MillwallMIL | → |  Wolverhampton WanderersWOL | Loan |
| 27 Sept 13 | L. Feeney Liam Feeney | MillwallMIL | → |  Bolton WanderersBOL | Loan |
| 19 Sept 13 | J. Marquis John Marquis | MillwallMIL | → |  PortsmouthPOR | Loan |
| 12 Sept 13 | P. Connolly Paul Connolly | XXX | → | MillwallMIL | Free |
| 12 Sept 13 | M. Waghorn Martyn Waghorn |  Leicester CityLEI | → | MillwallMIL | Loan |
| 02 Sept 13 | D. N'Guessan Dany N'Guessan | MillwallMIL | → |  Swindon TownSWI | Free |
| 08 Aug 13 | S. Derry Shaun Derry |  Queens Park RangersQPR | → | MillwallMIL | Loan |
| 08 Aug 13 | A. Marshall Andy Marshall | XXX | → | MillwallMIL | Free |
| 23 Jul 13 | S. McDonald Scott McDonald | MiddlesbroughMID | → | MillwallMIL | Free |
| 22 Jul 13 | N. Bailey Nick Bailey | XXX | → | MillwallMIL | Free |
| 17 Jul 13 | R. Chaplow Richard Chaplow |  SouthamptonSOU | → | MillwallMIL | Free |
| 17 Jul 13 | R. Chaplow Richard Chaplow | SouthamptonSOU | → | MillwallMIL | Free |
| 04 Jul 13 | L. Martin Lee Martin |  Ipswich TownIPS | → | MillwallMIL | Free |
| 02 Jul 13 | C. Wilkinson Conor Wilkinson | MillwallMIL | → | Bolton WanderersBOL | Undisclosed |
| 01 Jul 13 | S. Morison Steve Morison |  Leeds UnitedLEE | → | MillwallMIL | Free |
| 01 Jul 13 | C. Taylor Chris Taylor | MillwallMIL | → |  Blackburn RoversBLK | Free |
| 01 Jul 13 | S. Bywater Stephen Bywater |  Sheffield WednesdaySHW | → | MillwallMIL | Free |
| 28 Mar 13 | S. St. Ledger Sean St. Ledger | Leicester CityLEI | → | MillwallMIL | Loan |
| 27 Mar 13 | T. Bender Thomas Bender | XXX | → | MillwallMIL | Free |
| 15 Mar 13 | T. Mkandawire Tamika Mkandawire | MillwallMIL | → |  Southend UnitedSOUT | Loan |
| 15 Mar 13 | R. Chaplow Richard Chaplow | SouthamptonSOU | → | MillwallMIL | Loan |
| 15 Mar 13 | J. Easter Jermaine Easter |  Crystal PalaceCRY | → | MillwallMIL | Loan |
| 15 Mar 13 | R. Chaplow Richard Chaplow | SouthamptonSOU | → | MillwallMIL | Loan |
| 04 Mar 13 | J. Goodman Jake Goodman | MillwallMIL | → |  Luton TownLUT | Loan |
| 28 Feb 13 | G. Saville George Saville |  ChelseaCHE | → | MillwallMIL | Loan |
| 28 Feb 13 | G. Saville George Saville | ChelseaCHE | → | MillwallMIL | Loan |
| 13 Feb 13 | A. O'Brien Aiden O'Brien | MillwallMIL | → |  Crawley TownCRA | Loan |
| 08 Feb 13 | T. Racon Therry Racon | MillwallMIL | → | PortsmouthPOR | Loan |
| 08 Feb 13 | B. Afobe Benik Afobe |  ArsenalARS | → | MillwallMIL | Loan |
| 08 Feb 13 | B. Afobe Benik Afobe | ArsenalARS | → | MillwallMIL | Loan |
| 31 Jan 13 | A. Smith Adam Smith |  Tottenham HotspurTOT | → | MillwallMIL | Loan |
| 31 Jan 13 | A. Smith Adam Smith | Tottenham HotspurTOT | → | MillwallMIL | Loan |
| 31 Jan 13 | S. Batt Shaun Batt | MillwallMIL | → | Leyton OrientLEY | Loan |
| 29 Jan 13 | R. Hulse Robert Hulse | Queens Park RangersQPR | → | MillwallMIL | Loan |
| 29 Jan 13 | R. Hulse Robert Hulse | Queens Park RangersQPR | → | MillwallMIL | Loan |
| 09 Jan 13 | M. Woolford Martyn Woolford | Bristol CityBRC | → | MillwallMIL | Undisclosed |
| 04 Jan 13 | D. Ward Darren Ward | MillwallMIL | → | Swindon TownSWI | Free |
| 01 Jan 13 | S. Mildenhall Steve Mildenhall | MillwallMIL | → |  Bristol RoversBRI | Loan |
| 01 Jan 13 | M. Beevers Mark Beevers | Sheffield WednesdaySHW | → | MillwallMIL | Undisclosed |