The decision was made at a UN meeting in South Korea on Sunday.
The 2,918-metre Mount Olympus is noted for both its rich biodiversity and its role in Greek mythology.
In Japan, 19 archaeological sites in Nara Prefecture from the 6th to 7th centuries are also listed as World Heritage Sites. The area includes the remains of palaces and Buddhist temples.
South Sudan also received its first World Heritage Site when the Boma-Badingilo Migration Landscape was inscribed on the list. The area is home to one of the world's largest mammal migrations, where around six million antelopes move across the savannah.
