Internetwork Packet Exchange (IPX) is the network layer protocol in the IPX/SPX protocol suite. IPX is derived from Xerox Network Systems' IDP. It also has the ability to act as a transport layer protocol.

The IPX/SPX protocol suite was very popular through the late 1980s and mid-1990s because it was used by Novell NetWare, a network operating system. Due to Novell NetWare's popularity, IPX became a prominent protocol for internetworking.

A big advantage of IPX was a small memory footprint of the IPX driver, which was vital for DOS and Windows up to Windows 95 due to the limited size at that time of conventional memory. Another IPX advantage is easy configuration of its client computers. However, IPX does not scale well for large networks such as the Internet. As such, IPX usage decreased as the boom of the Internet made TCP/IP nearly universal.

Computers and networks can run multiple network protocols, so almost all IPX sites also run TCP/IP, to allow Internet connectivity. It is also possible to run later Novell products without IPX, with the beginning of full support for both IPX and TCP/IP by NetWare version 5 in late 1998.