MPE is an early 1980s era business oriented minicomputer operating system made by Hewlett-Packard.

It runs on HP's 3000 series computers, which originally used HP custom CISC CPUs and were later migrated to PA-RISC. The name of the OS was changed to MPE/iX to indicate Unix interoperability. The product line is in deep maintenance mode as of 2003 and will be completely ended in a few years; the user-base is much smaller than that of its old competitors OS/400 and VMS and no further product introductions are expected.