Prep may refer to:
- A nickname for anything associated with a University-preparatory school, such as:
- A member of the American Preppy social group, stemming from the word "preparatory"
- Another name for someone who attends a preparatory school in the United States
- Prep, a novel by Curtis Sittenfeld
- Prep, short form for a plasmid preparation (including minipreps and bulk preps) or the DNA prepared by such a method
- Prep, short form for preparation of or for something
- PReP, the PowerPC Reference Platform
- P-rep, a statistical value of the probability of replicating an observed effect
- Preparative, a NATO signal flag
- Presequence Protease, a mitochondrial and chloroplastic protein
- Pre-Exposure Prophylaxis, a medical procedure to prevent disease before exposure