Seira may refer to:
- Seira, Estonia, a village in Estonia
- Seira, Aragon, a municipality in Aragon, Spain
- Seira (springtail), a genus of slender springtails
- SEIRA, surface-enhanced infrared absorption spectroscopy, see List of materials analysis methods#S
- Seira Nakayama (中山 セイラ) (born 1983), Japanese sabre fencer
- Seira Ryū (劉 セイラ) (born 1985), Chinese–Japanese voice actress
- Seira, a character in the manga series Mermaid Melody Pichi Pichi Pitch
- Seira, a character in the anime series Endro!