An Istanbul court found Dutch defender Jayden Oosterwolde and Turkish attacking midfielder Mert Hakan Yandaş guilty of "assault and battery".
The victim was Galatasaray stadium director Ali Celikkiran who was diagnosed with a neck fracture, according to a medical report cited in the indictment.
The attack took place in May 2024 after a tense derby between the two sides.
Contacted by AFP, Fenerbahce declined to comment on the court's verdict.
The Istanbul derby, won by Fenerbahce (1–0), took place on the penultimate matchday of the Turkish league.
Galatasaray ultimately clinched the title in the final game of the season.