| 2017−18 LEN Euro Cup | |
| League: | LEN Euro Cup |
| Sport: | Water Polo |
| Pixels: | 180px |
| Duration: | 27 September 2017 to 18 April 2018 |
| No Of Teams: | 17 |
| Finals Champ: |  Ferencváros (2nd title) |
| Finals Runner-Up: |  Banco BPM SM Busto |
| Seasonslist: | LEN Euro Cup |
| Seasonslistnames: | Euro Cup |
| Prevseason Link: | 2016–17 LEN Euro Cup |
| Prevseason Year: | 2016–17 |
| Nextseason Link: | 2018–19 LEN Euro Cup |
| Nextseason Year: | 2018−19 |
The 2017–18 LEN Euro Cup was the second tier of European competition in water polo. It ran from 27 September 2017 to 18 April 2018.
| Qualification round I | ||||
|---|---|---|---|---|
| Jadran Split | WS Hannover |  Shturm 2002 | ||
 Montpellier |  Primorac Kotor | |||
| ZPC Amersfoort |  Hornets Košice | |||
| Quarter-finals | ||||
The schedule of the competition is as follows.[1]
| Phase | Round | First leg | Second leg |
|---|---|---|---|
| Qualifying | Qualification round I | 27 September–1 October 2017 | |
| Qualification round II | 13–15 October 2017 | ||
| Knockout stage | Quarter-finals | 8 November 2017 | 9 December 2017 |
| Semi-finals | 24 January 2018 | 28 February 2018 | |
| Final | 31 March 2018 | 18 April 2018 | |
|}
|}
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