In the 1988 Summer Olympics, together with teammate Arvydas Sabonis, Marčiulionis led the senior USSR national team to the gold medal. With the senior Lithuanian national team, he won two Summer Olympics bronze medals, in 1992 and 1996. He was an All-Tournament Team member, the top scorer, and the MVP of the EuroBasket 1995, and he was also elected to the All-EuroBasket Team in 1987.