The Tristan moorhen or Tristan gallinule (Gallinula nesiotis) is an extinct species of flightless rail endemic to the South Atlantic island of Tristan da Cunha.

The once abundant Tristan moorhen had become rare by 1873, and by the end of 19th century it was extinct as a result of hunting, predation by introduced species (rats, cats and pigs) and habitat destruction by fire.

A handful of taxidermied specimens of the Tristan moorhen have been preserved.

In 1956 the closely related Gough moorhen G. comeri was introduced to Tristan da Cunha, under the then belief it was a reintroduction of the same species.

[3] On the basis of DNA sequencing of both recently collected and historical material from both species, Groenenberg et al (2008) concluded that the genetic distances between G. nesiotis and G. comeri are of at least the same size as those found between subspecies of G. chloropus in the literature.