Allegra may refer to:
- A fictional character
- Allegra, the main character on the 1994–1996 Nick Jr. television series Allegra's Window
- Allegra Geller, fictional character in the 1999 film eXistenZ
- A person
- Allegra (given name), people with the given name Allegra
- Gabriele Allegra Italian Catholic priest, declared Venerable (1907-1976)
- Salvatore Allegra (1898–1993), Italian composer
- Other
- Allegra, 1999 live album by Fifteen (band)
- Allegra, a healthcare software development company in South Africa
- Fexofenadine, an antihistamine drug sold under the brand names Allegra, Allerfexo, Telfast and others
- Rhaetian Railway ABe 8/12, a powerful three-car Electric Multiple Unit on Swiss meter gauge