Orchid cactus is an English name for a plant which may refer to:

Epiphyllum hybrid 'Unforgettable'

• Epiphyllum hybrid, one of a number of hybrid cacti formed by crosses between Disocactus, Pseudorhipsalis, Selenicereus and Epiphyllum; often collectively called "epiphyllums" or "epis"
• Epiphyllum, one or more of the species of this genus.
• Disocactus ×hybridus, a hybrid cactus often incorrectly called Disocactus ackermannii