The koteka, horim, penis gourd or penis sheath is a phallocrypt or phallocarp traditionally worn by native male inhabitants of some (mainly highland) ethnic groups in New Guinea to cover their genitals. They are normally made from a dried out gourd, Lagenaria siceraria, although other species, such as Nepenthes mirabilis, are also used. They are held in place by a small loop of fiber attached to the base of the koteka and placed around the scrotum. There is a secondary loop placed around the chest or abdomen and attached to the main body of the koteka. Men choose kotekas similar to ones worn by other men in their cultural group. For example, Yali men favour a long, thin koteka, which helps hold up the multiple rattan hoops worn around their waist. Men from Tiom wear a double gourd, held up with a strip of cloth, and use the space between the two gourds for carrying small items such as money and tobacco.

It is traditional clothing in certain New Guinea highlands societies including in the Grand Baliem Valley of Western New Guinea and the Ok Tedi and Telefomin regions of Papua New Guinea. It is worn without other clothing, tied in upward position (see image).