Jenny may refer to:

• The diminutive form of the name Jennifer; see Jennifer for a list of famous people with the name of Jenny and its variations
• A slang term for a weak person, object, or concept whose usage requires little regard for preservation
• A slang term for the Curtiss JN4 Biplane flown during World War I that was popular for Barnstorming
• A female donkey (ass)
• 867-5309/Jenny, a song by Tommy Tutone
• Jenny Craig, a weight loss guru who founded the Jenny Craig Weight Loss Plan
• A popular Japanese fashion doll
• Spinning jenny, a device used in the textile industry (where jenny is possibly a corruption of engine)
• Inverted Jenny, a famous United States Postage Stamp error
• Jenny Sparks, the Spirit of the 20th Century in The Authority comic books
• Jenny Quantum, the Spirit of the 21st Century, successor to Jenny Sparks in The Authority comic books
• Jenny Suico, a Filipino contestant of Pinoy Big Brother
• Jennifer Serrano, a Spanish singer better known as Jenny
• Jenny Everywhere, an open source fictional character
• Jenny, a diminutive form of Jennifer coming from the celtic Gwenwyfer (later Guinivere) meaning white wave or white ghost
• Jennifer Ringley, the star of the JenniCam website