2017–18 Ekstraklasa
The 2017–18 Ekstraklasa was the 92nd season of the Polish Football Championship and the 84th season of the Ekstraklasa, the top Polish professional league for association football clubs, since its establishment in 1927. The league is operated by the Ekstraklasa S.A.
The season started on 14 July 2017 and concluded on 20 May 2018. After the 21st matchday the league went on a winter break between 18 December 2017 and 9 February 2018. The regular season was played as a round-robin tournament. A total of 16 teams participated, 14 of which competed in the league during the 2016–17 season, while the remaining two were promoted from the I liga after the 2016-17 season. The fixtures were announced on 8 June 2017.
Each team played a total of 30 matches, half at home and half away. After the 30th round, the league split into two groups: championship round and relegation round. Each team played 7 more games. So, finally each team played a total of 37 matches. The team at the top of the Championship round wins the league title. The two teams at the bottom of the Relegation round are demoted to I liga for the 2018-19 season. This was the fifth season to take place since the new playoff structure has been introduced.
The defending champions were Legia Warsaw, who won their 12th Polish title the previous season.
Legia successfully defended their title, sealing the league trophy for a 13th time in dramatic circumstances as their deciding game against Lech Poznan was abandoned due to flares and pitch invasions by Lech fans. Legia were awarded the tie 3-0 and three points secured 1st place.
Teams
Sixteen teams will compete in the league – the top fourteen teams from the previous season, as well as two teams promoted from the I liga. Sandecja Nowy Sącz were promoted to the Ekstraklasa for the first time. Górnik Zabrze returned to Ekstraklasa after a one-year absence.Stadiums and locations
| Team | Location | Venue | Capacity |
| Arka Gdynia | Gdynia | Stadion Miejski | 15,139 |
| Bruk-Bet Termalica Nieciecza | Nieciecza | Stadion Bruk-Bet Termaliki | 4,653 |
| Cracovia | Kraków | Stadion Cracovii | 15,016 |
| Górnik Zabrze | Zabrze | Stadion im. Ernesta Pohla | 24,413 |
| Jagiellonia Białystok | Białystok | Stadion Miejski | 22,432 |
| Korona Kielce | Kielce | Kolporter Arena | 15,550 |
| Lech Poznań | Poznań | INEA Stadion | 43,269 |
| Lechia Gdańsk | Gdańsk | Stadion Energa Gdańsk | 43,615 |
| Legia Warsaw | Warsaw | Stadion im. Marszałka Józefa Piłsudskiego | 31,800 |
| Piast Gliwice | Gliwice | Stadion Miejski | 10,037 |
| Pogoń Szczecin | Szczecin | Stadion im. Floriana Krygiera | 18,027 |
| Sandecja Nowy Sącz | Nieciecza | Stadion Bruk-Bet Termaliki | 4,653 |
| Śląsk Wrocław | Wrocław | Stadion Miejski | 42,771 |
| Wisła Kraków | Kraków | Stadion im. Henryka Reymana | 33,326 |
| Wisła Płock | Płock | Stadion im. Kazimierza Górskiego | 12,800 |
| Zagłębie Lubin | Lubin | Stadion Zagłębia | 16,068 |
- Sandecja Nowy Sącz will play their home games in Nieciecza until their home ground fulfills license requirements.
- Upgrading to 31,871.