The shooting of the 16-year-old has sparked violent protests and the Roma community says his ethnicity was a factor.
He had been in a critical condition after emergency surgery since the 5 December incident.
A hospital in Thessaloniki, Greece’s second-biggest city, said that despite “tireless efforts” the boy died on Tuesday morning.
Antonis Tasios, secretary of the Roma community where the teenager lived, said: “Everyone here is crying. It is unjust for a child to leave like this. We have great pain.”
A 34-year-old police officer has been charged with attempted manslaughter and illegally firing his gun.
About 200 people from the Roma community demonstrated outside court when he appeared on Friday. Continue