The Silurians are a race of reptilian humanoids in the long-running British science fiction television series Doctor Who. The species first appeared in Doctor Who in the 1970 serial Doctor Who and the Silurians, and were created by Malcolm Hulke. The first Silurians introduced are depicted as prehistoric and scientifically advanced sentient humanoids who predate the dawn of man; in their backstory, the Silurians went into self-induced hibernation to survive what they predicted to be a large atmospheric upheaval caused by the Earth capturing the Moon.

The Silurians introduced in the 1970 story are broad, three-eyed land-dwellers. The 1972 serial The Sea Devils, also by Hulke, introduced their eponymous amphibious cousins. Both Silurians and Sea Devils made an appearance in 1984's Warriors of the Deep, and did not appear in the show again before its cancellation in 1989. Following the show's revival in 2005, heavily redesigned Silurans were reintroduced to the series in 2010, and have recurred frequently since then, while the Sea Devils first reappeared in 2022, with their designs mostly unchanged. In 2018 the real-life scientists Adam Frank and Gavin Schmidt named their Silurian hypothesis for the fictional species.

Commonly called Silurians, after their supposed origins in the Silurian period, the creatures have also been referred to by other names. In The Sea Devils, the Third Doctor (Jon Pertwee) claims that "properly speaking", the Silurians should have been called "Eocenes". The name Homo reptilia is first used to describe the creatures in the novelisation Doctor Who and the Cave-Monsters (1974), and is first used in the series proper in the episode "The Hungry Earth" (2010). In The Sea Devils, an amphibious Silurian is dubbed a "Sea Devil" by the human workman Clark (Declan Mulholland), while in Warriors of the Deep, the land-dwelling Silurians use the term "Sea Devil" to refer to their aquatic counterparts.