| 08 Aug 18 | B. Simakala Ba-Muaka Simakala |  Borussia MonchengladbachMON | → | RKXRoda KerkradeRoda Kerkrade | Undisclosed |
| 13 Jul 18 | J. Vestergaard Jannik Vestergaard | Borussia MonchengladbachMON | → |  SouthamptonSOU | Undisclosed |
| 13 Jul 18 | A. Pléa Alassane Pléa |  NiceNICE | → | Borussia MonchengladbachMON | Undisclosed |
| 13 Jul 18 | J. Vestergaard Jannik Vestergaard | Borussia MonchengladbachMON | → | SouthamptonSOU | Undisclosed |
| 13 Jul 18 | A. Pléa Alassane Pléa | NiceNICE | → | Borussia MonchengladbachMON | Undisclosed |
| 01 Jul 18 | R. Bobadilla Raúl Marcelo Bobadilla | Borussia MonchengladbachMON | → |  Argentinos JuniorsARGJ | Undisclosed |
| 01 Jul 18 | K. Bennetts Keanan Bennetts |  Tottenham HotspurTOT | → | Borussia MonchengladbachMON | Undisclosed |
| 01 Jul 18 | J. Blaswich Janis Blaswich | Borussia MonchengladbachMON | → |  Heracles AlmeloHER | Undisclosed |
| 01 Jul 18 | R. Bobadilla Raúl Marcelo Bobadilla | Borussia MonchengladbachMON | → | Argentinos JuniorsARGJ | Undisclosed |
| 01 Jul 18 | V. Grifo Vincenzo Grifo | Borussia MonchengladbachMON | → |  TSG HoffenheimHOF | Undisclosed |
| 01 Jul 18 | M. Lang Michael Lang |  FC BaselBAS | → | Borussia MonchengladbachMON | Undisclosed |
| 01 Jul 18 | A. Poulsen Andreas Poulsen |  FC MidtjyllandMIDT | → | Borussia MonchengladbachMON | Undisclosed |
| 01 Jul 18 | T. Müsel Torben Müsel |  KaiserslauternFCK | → | Borussia MonchengladbachMON | Free |
| 01 Jul 18 | J. Blaswich Janis Blaswich | Borussia MonchengladbachMON | → | Heracles AlmeloHER | Undisclosed |
| 01 Jul 18 | K. Bennetts Keanan Bennetts | Tottenham HotspurTOT | → | Borussia MonchengladbachMON | Undisclosed |
| 11 Jun 18 | V. Grifo Vincenzo Grifo | Borussia MonchengladbachMON | → | TSG HoffenheimHOF | Undisclosed |
| 11 Jun 18 | T. Müsel Torben Müsel | KaiserslauternFCK | → | Borussia MonchengladbachMON | Undisclosed |
| 08 Jun 18 | C. Theoharous Christian Theoharous |  Melbourne VictoryMVC | → | Borussia MonchengladbachMON | Undisclosed |
| 08 Jun 18 | C. Theoharous Christian Theoharous | Melbourne VictoryMVC | → | Borussia MonchengladbachMON | Undisclosed |
| 31 Jan 18 | R. Oxford Reece Oxford |  West Ham UnitedWHU | → | Borussia MonchengladbachMON | Loan |
| 31 Jan 18 | R. Oxford Reece Oxford | West Ham UnitedWHU | → | Borussia MonchengladbachMON | Loan |
| 23 Jan 18 | K. Yeboah Kwame Yeboah | Borussia MonchengladbachMON | → | PXXPaderbornPaderborn | Loan |