LUP may refer to:
- Lift Upgrading Programme, a Singapore Housing and Development Board (HDB) project
- Lead units of pressure, a measurement for the estimation of chamber pressures in firearms
- Kalaupapa Airport, Hawaii (IATA Code: LUP)
- LUP decomposition, a matrix decomposition useful in solving an n-by-n systems of linear equations
- Leiden University Press, a publishing house and part of Leiden University
- Liberty Union Party, a political party of Vermont, USA
- Lifeless undead phenomenon, a term originating in the Richard Matheson story " Dance of the Dead"