In geometry, the pentagonal orthobicupola is one of the Johnson solids (J_30). As the name suggests, it can be constructed by joining two pentagonal cupolae (J_5) along their decagonal bases, matching like faces. A 36-degree rotation of one cupola before the joining yields a pentagonal gyrobicupola (J_31). The pentagonal orthobicupola is the third in an infinite set of orthobicupolae.