The 2015–16 Eurocup Basketball Regular Season was played from 13 October to 16 December 2015.
A total of 36 teams competed in the group stage to decide the 24 places in the Last 32 with the 8 places dropped from the Euroleague Regular Season.
In each group, teams played against each other home-and-away in a round-robin format.
The four first qualified teams advanced to the Last 32, while the fifth and the sixth-placed teams was eliminated.
If teams are level on record at the end of the Regular Season, tiebreakers are applied in the following order: