Lancet may refer to:
- In medicine:
- Lancet (surgery), a cutting instrument (scalpel) with a double-edged blade
- Blood lancet, a pricking needle used to obtain drops of blood for testing
- The Lancet, a medical journal
- In architecture:
- Lancet arch, a narrow, tall opening with a pointed arch
- Lancet window, a window set in a lancet arch