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
The IUP Portable User Interface is a computer software development kit that provides a portable, scriptable toolkit to build graphical user interfaces (GUIs) using the programming languages C, Perl, Lua and Nim. This allows rapid, zero-compile prototyping and refinement of deployable GUI applications.
IUP's purpose is to allow programs to run in different systems in unmodified form.
It provides this ability by binding Lua with its C/C++ code, or simply writing C to the application programming interface (API). It supports calling native Windows API graphics, native Motif- LessTif or GTK+ elements, or the developers' own CanvasDraw elements from the Lua scripts or natively in a C/C++ application.