The 2017–18 National Basketball League (Czech Republic) season is the 25th season of the Czech NBL.
After the end of the stage after the first split, the six teams from to top group and the two first qualified teams from the bottom group joined the play-offs.
The other four teams would play again home and away against themselves for avoiding the relegation.
Olomoucko replaced Ariete Prostějov, which was relegated from the previous season and was dissolved.
Seeded teams played at home games 1, 2, 5 and 7, while the third place game where played with a best-of-three format, playing the seeded team the matches 1 and 3 at home, and the finals in a double-legged one.