The IBM 5120 Computing System is a 16-bit microcomputer developed by IBM and released in February 1980. Marketed as the desktop follow-on to the portable IBM 5110 Computing System, it featured two built-in 8-inch 1.2 MB floppy disk drives, an integrated 9-inch monochrome monitor, 32 KB RAM, plus an optional IBM 5114 stand-alone diskette unit with two additional 8-inch 1.2 MB floppy disk drives.

The IBM 5110 Computing System is the successor of the IBM 5100 Portable Computer.