StuffIt is a discontinued family of computer software utilities for archiving and compressing files. Originally produced for the Macintosh, versions for Microsoft Windows, Linux (x86), and Sun Solaris were later created. The proprietary compression format used by the StuffIt utilities is also termed StuffIt.

In December 2019, Smith Micro Software, the product's most-recent owner and developer, officially announced that StuffIt had reached its end-of-life and that StuffIt products would no longer be developed. One last update did come out in December 2020 after the launch of the Apple M1 architecture to support that and Intel Mac systems through a universal binary of the program.