Disa is a genus of flowering plants in the family Orchidaceae. It comprises about 182 species. Most of the species are indigenous to tropical and southern Africa, with a few more in the Arabian Peninsula, Madagascar, and Réunion. Disa bracteata is naturalised in Western Australia, where the local name is "African weed-orchid."

The genus Disa was named by P.J. Bergius in 1767. It was named after Disa, the heroine of a Swedish legend.

The plants grow from a fleshy tuberous root which is a source of maltodextrins which are used as a sugar substitute. Some species attain a height of 90 cm (35 in). The flowers are solitary or arranged in racemes. The petals and the lip are small. The flowers consist essentially of the sepals. The flowers range in color from very light to dark red.

Disa exhibits a variety of pollination syndromes. Each species of Disa usually has a single species as pollinator and nearly every available pollinating insect is employed by some species of Disa. Species that adapted to the same pollinator often independently evolved a similar floral morphology which confounded the infrageneric classification of Disa until cladistic analysis was applied to DNA sequences from this genus.

Examples of convergent evolution in Disa pollination include the following:

Disa serves as an example of how speciation can be caused by changes in pollinator availability and evolution.

Some Disa species are pollinated by sunbirds and have pollinaria that stick to the feet of the sunbirds when they perch on the inflorescence.

The first molecular phylogeny of the genus involved comparison of nuclear ribosomal ITS1, 5.8S rDNA, and ITS2 sequences, and showed that Herschelia and Monadenia were nested within a paraphyletic Disa.