Selenicereus megalanthus, synonym Hylocereus megalanthus,[1] is a cactus species in the genus Selenicereus that is native to northern South America, where it is known, along with its fruit, by the name of pitahaya.

The species is grown commercially for its yellow fruit, but is also an impressive ornamental climbing vine with perhaps the largest flowers of all cacti.

The yellow skinned fruit of S. megalanthus has thorns, unlike the green, red or yellow skinned dragon fruits of S. undatus, S. monacanthus and their cultivated hybrids.

This name leads at times to confusion, as unrelated cultivars of other dragonfruit species can also have yellow skinned fruit.

The species is native to Colombia, Costa Rica, Ecuador, Nicaragua, Panama, Peru, Trinidad and Tobago and Venezuela.