| 31 Aug 17 | L. Alario Lucas Alario |  River PlateCARP | → |  Bayer LeverkusenLEV | ?23,800,000 |
| 31 Aug 17 | A. Dragovic Aleksandar Dragovic | Bayer LeverkusenLEV | → |  LiverpoolLIV | Loan |
| 31 Aug 17 | L. Alario Lucas Alario | River PlateCARP | → | Bayer LeverkusenLEV | ?23,800,000 |
| 31 Aug 17 | K. Kampl Kevin Kampl | Bayer LeverkusenLEV | → |  RB LeipzigRBL | Undisclosed |
| 31 Aug 17 | A. Dragovic Aleksandar Dragovic | Bayer LeverkusenLEV | → | LiverpoolLIV | Loan |
| 31 Aug 17 | P. Retsos Panagiotis Retsos |  OlympiakosOLY | → | Bayer LeverkusenLEV | Undisclosed |
| 26 Jul 17 | T. Handwerker Tim Handwerker | Bayer LeverkusenLEV | → |  FC CologneCOL | Free |
| 24 Jul 17 | J. Hernández Javier Hernández | Bayer LeverkusenLEV | → |  West Ham UnitedWHU | 16000000 |
| 24 Jul 17 | J. Hernández Javier Hernández | Bayer LeverkusenLEV | → | West Ham UnitedWHU | 16000000 |
| 13 Jul 17 | S. Bender Sven Bender |  Borussia DortmundDOR | → | Bayer LeverkusenLEV | Undisclosed |
| 13 Jul 17 | R. Seung-Woo Ryu Seung-Woo | Bayer LeverkusenLEV | → | JUXJeju UnitedJeju United | Undisclosed |
| 03 Jul 17 | H. Calhanoglu Hakan Calhanoglu | Bayer LeverkusenLEV | → |  AC MilanMIL | Undisclosed |
| 03 Jul 17 | H. Calhanoglu Hakan Calhanoglu | Bayer LeverkusenLEV | → | AC MilanMIL | Undisclosed |
| 01 Jul 17 | Ö. Toprak Ömer Toprak | Bayer LeverkusenLEV | → | Borussia DortmundDOR | Undisclosed |
| 01 Jul 17 | Danny Da Costa | Bayer LeverkusenLEV | → |  TSG HoffenheimHOF | Undisclosed |
| 28 Jun 17 | K. Papadopoulos Kyriakos Papadopoulos | Bayer LeverkusenLEV | → |  Hamburg SVHSV | Undisclosed |
| 31 Jan 17 | L. Bailey Leon Bailey |  Racing GenkGENK | → | Bayer LeverkusenLEV | Undisclosed |
| 22 Jan 17 | R. Kruse Robbie Kruse | Bayer LeverkusenLEV | → |  Liaoning WhowinLIAO | Undisclosed |
| 17 Jan 17 | K. Papadopoulos Kyriakos Papadopoulos | Bayer LeverkusenLEV | → | Hamburg SVHSV | Loan |