Info-ZIP is a set of open-source software to handle ZIP archives. It has been in circulation since 1989. It consists of 4 separately-installable packages: the Zip and UnZip command-line utilities; and WiZ and MacZip, which are graphical user interfaces for archiving programs in Microsoft Windows and classic Mac OS, respectively.

Info-ZIP's Zip and UnZip have been ported to dozens of computing platforms. The UnZip web page describes UnZip as "The Third Most Portable Program in the World", surpassed by Hello World, C-Kermit, and possibly the Linux kernel. The "zip" and "unzip" programs included with most Linux and Unix distributions are Info-ZIP's Zip and UnZip.

In addition to the Info-ZIP releases themselves, parts of Info-ZIP, including zlib, have been used in numerous other file archivers and other programs. Many Info-ZIP programmers have also been involved in other projects closely related to the DEFLATE compression algorithm, such as the PNG image format and the zlib software library.

The UnZip package also includes three additional utilities:

The Zip package includes three additional utilities:

UnZip 1.0 (March 1989) was released by Samuel M. Smith. It was written in Pascal and C. Pascal was abandoned soon after.

UnZip 2.0 (September 1989) was released by Samuel M. Smith. It included support for the "unimploding" (method 6) introduced by PKZIP 1.01. George Sipe created Unix version.

UnZip 2.0a (December 1989) was released by Carl Mascott and John Cowan.