Opatje Selo (Slovene: Opatje selo, Italian: Opacchiasella) is a village in the Municipality of Miren–Kostanjevica in the Littoral region of Slovenia, right on the border with Italy. It is located on the Karst Plateau, along an old road leading from Komen to Gorizia (and Nova Gorica).
The parish church in the settlement is dedicated to Saint Andrew and belongs to the Diocese of Koper.
The name of the village means 'abbot's village' in Slovene. The name derives from the 12th century, when the village was first mentioned, because it was owned by the Benedictine monastery in the nearby Duino.
During World War I, the Battles of the Isonzo between Austria-Hungary and Italy took place here.
It is the native village of the Yugoslav politician Drago Marušič, governor of the Drava Banovina (1930–1934), minister in several Yugoslav governments, and co-regent of Yugoslavia between 1944 and 1946.