Darko Kostić (Serbian Cyrillic: Дарко Костић, Greek: Ντάρκο Ράλλη (Ntarko Rallis); born 30 September 1978) is a Serbian–Greek professional basketball coach and former player.
Rallis had two stints with the Belgian team Okapi Aalstar where played during 1998–99 and 2000–01 season.
[1][2] In 2003, he moved to Slovakia where he played for two seasons for Chemosvit Svit and MBK Lučenec.
On 30 July 2018 Kostić became a head coach for Bulgarian team Academic Bultex 99.
[8] On 4 January 2019, Kostić was named as a head coach of Vršac of the Basketball League of Serbia.