Snake oil might refer to:
- Genuine snake lipid in liquid (oil) form used in traditional herbal treatments, such as Chinese medicine
- Patent medicines, some of which were once marketed as "snake oil"
- Woo of any kind
- Cryptography-related woo, or any insecure cryptography
- Computer security software of questionable efficacy, especially "Personal Firewall" and sometimes "Anti-Virus" programs, which may provide the user with a false sense of security while actually increasing the system's complexity and hence risk introducing additional attack vectors.
- Karl Rove
- Somebody who has consumed too much snake oil for their own good is known as a Kool-Aid drinker.