IUP may refer to:

• Indiana University of Pennsylvania, the largest of the state-owned universities in the Pennsylvania State System of Higher Education
• IUP Crimson Hawks, the intercollegiate athletic program of the above school
• IUP Portfolio, a Swedish short for individual development plan
• IUP (software), a computer software that provides a portable, scriptable toolkit for GUI building.
• Industrial Union Party
• Interconnect User Part, UK specific SS7 protocol
• Inter-University Program for Chinese Language Study at Tsinghua University
• Intrauterine Pregnancy, the normal location for a pregnancy to occur
• Intrinsically unstructured protein
• Irish Unionist Party, an alternate name for the Irish Unionist Alliance, a political party founded in 1891.

• Naval Aircraft Factory TR-2
• Naval Aircraft Factory TS-2
• Naval Aircraft Factory TS-3
• Naval Aircraft Factory XOSN
• Naval Aircraft Factory XP2N
• Naval Aircraft Factory XP4N
• Naval Aircraft Factory XP4N-1
• Naval Aircraft Factory XP4N-2
• Naval Aircraft Modification Unit
• Naval Aircraft Modification Unit KA2N Gorgon
• Naval Aircraft Modification Unit KD2N Gorgon
• Naval Aircraft Modification Unit KDN Gorgon
• Naval Aircraft Modification Unit KGN
• Naval Aircraft Modification Unit KGN Gorgon IIC
• Naval Aircraft Modification Unit KU2N Gorgon
• Naval Aircraft Modification Unit KUN
• Naval Aircraft Modification Unit KUN Gorgon
• Naval Aircraft Modification Unit KUN Gorgon IIC
• Naval Aircraft Modification Unit TD3N Gorgon
• Naval Aircraft Support Unit, Culdrose
• Naval Air Department
• Naval Air Division
• Naval Air Division (Royal Navy)
• Naval Air Engineering Station Lakehurst
• Naval Air Facility Kadena