| John Sinis Γιάννης Σίνης | |
| Position: | Power forward / center |
| Height Ft: | 6 |
| Height In: | 9 |
| Weight Lbs: | 236 |
| Team: | Free agent |
| Nationality: | Greek |
| Birth Date: | September 4, 1991 |
| Birth Place: | Patras, Greece |
| College: | San Diego (2011–2013) |
| Draft Year: | 2014 |
| Career Start: | 2013 |
| Years1: | 2013–2015 |
| Team1: | Rethymno Cretan Kings |
| Years2: | 2015–2016 |
| Team2: | Kavala |
| Years3: | 2016–2017 |
| Team3: | Psychiko |
| Years4: | 2017–2018 |
| Team4: | Arkadikos |
John Sinis, or Giannis Sinis (Greek: Γιάννης Σίνης; born September 4, 1991), is a Greek professional basketball player. He is 2.06m (06.76feet) tall.[1] He plays at the power forward and center positions.
Sinis played college basketball at the University of San Diego with the Toreros.
Sinis began his professional career with the top-tier level Greek Basket League club Rethymno Cretan Kings in 2013. In 2015, he moved to Kavala.[2] He missed the season, due to injury.
In 2016, he signed with the Psychiko of the 2nd-tier level Greek A2 Basket League.[3]