St. Panteleimon Monastery (Greek: Άγιος Παντελεήμων, Aghios Panteleimon;Russian: Пантелеймонов, known as Ρωσσικόν, Rossikon), is a Russian Orthodox monastery built on the south-west side of the peninsula of Mt. Athos in Greece. It is the largest of the many monasteries on the peninsula.