The Silurian is the geological period and system lasting roughly from 445 million years ago to 415 million years ago.
Silurian may also refer to:
- Silurian, the society, culture, language, and ethnicity of the Silures, an ancient Welsh tribe
- Silurian, the racehorse that won the 1923 Doncaster Cup
- Silurian Press Club, the society established at 1924 by a group of maverick Park Row newspaper veterans
- Silurian (Doctor Who), a fictional race of humanoid reptiles who existed before humanity
- Silurian hypothesis, a thought experiment that speculates if a prior advanced civilization on Earth would leave behind present day evidence of its existence
- Silurian Hills, a small range of hills in the Mojave Desert
- Siluria Technologies, a San Francisco-based technology company
- Eriopygodes imbecilla, the Silurian, a moth of the family Noctuidae