The 2017–18 Országos Bajnokság I was the 35th season of the Országos Bajnokság I, Hungary's premier Water polo league.
The following 10 clubs compete in the OB I during the 2017–18 season: In the table below the home teams are listed on the left and the away teams along the top.
BVSC-Zugló Diapolo won the series 9–0 with points ratio, and advanced to the Semifinals.
Ferencvárosi TC won the series 9–0 with points ratio, and advanced to the Semifinals.
The lower ranked hosted Game 2.