Jaco (also sometimes written as Jako) is a small island in the Lesser Sunda Islands. It lies across from the easternmost point of the island of Timor, Kap Cutcha. Its geographical coordinates are 8° 27' S and 127° 20' E. Politically it is part of the subdistrict of Tutuala within Lautém district of East Timor. It is separated from the mainland by a narrow channel, suitable for passage by small vessels only. It is about 10 square kilometers in area and reaches about 100 meters in altitude.
The island is uninhabited. It is considered holy by the indigenous population and entering the island was forbidden. In our days, tourists are taken by fishermen to the island for diving and swimming.