Xanthoulis studied Advanced Theoretical Subjects and Composition in the Athens Conservatory with Menelaos Palandios, Diamantis Diamantopoulos and Pericles Koukos. He received his PhD in Musicology from the Music Academy of Sofia, Bulgaria, for his dissertation on the “Polyphony of 1800”. The Examining Committee, which included Professor Dimiter Christoff, unanimously accepted the thesis—- the first time in 16 years.
Xanthoulis studied advanced theoretical subjects and composition at the Athens Conservatory under the guidance of Menelaos Palandios, Diamantis Diamantopoulos, and Pericles Koukos. He earned his PhD in Musicology from the Music Academy of Sofia, Bulgaria, for his dissertation on "Polyphony of 1800". The Examining Committee, composed of Professor Dimiter Christoff, unanimously approved his thesis after a long period of time.