The 2003–04 Greek Basket League season was the 64th season of the Greek Basket League, the highest tier professional basketball league in Greece. It was also the 12th season of Greek championship regulated by HEBA (ESAKE). The winner was Panathinaikos that won Maroussi in the finals of the championship.[1] The clubs Irakleio and Ilysiakos relegated in A2 Ethniki as well as Peristeri that was relegated because it faced financial problems.[2] Top scorer of the championship was Nestoras Kommatos, player of Aris.[3]