The Vidiians are a race in the Star Trek fictional universe that are under the affliction of a plague called the Phage. They possess medical technology far more advanced than anything known to man, as they must constantly replace their organs with transplants, often stolen, to remain alive. Their bodies appear to be made of a patchwork of different alien skins. In several episodes of Star Trek: Voyager, the Vidiians cause trouble, on several occasions they board the ship or steal organs from crew members. It was later discovered that the Vidiian people were not aware of the involuntary organ snatching, knowledge and activity of it being closely held by the government and/or military. The Vidiians were presented in a somewhat balanced way; the Vidiians said that they were driven to their organ-raids on other races out of extreme desperation, and that before the Phage struck they were a peaceful and cultured race of scientists and explorers, much like the Federation. Klingon physiology was resistant to the Phage, and with Klingon tissue samples Vidiian scientists hoped to find a treatment for the Phage.

The formal name of the Vidiians government is the "Vidiian Solidality" (Vidiian brotherhood).

Later in the run of Voyager, is was mentioned that the Vidiian Phage had been cured.