Microsoft Office and OpenOffice are both office productivity suites, but there are some key differences between the two. Microsoft Office is a proprietary suite of applications, while OpenOffice is an open-source, free alternative. Because of this, OpenOffice is available for a wider range of operating systems, including Linux and macOS, whereas Microsoft Office is only available for Windows and macOS. Additionally, OpenOffice has a slightly different set of applications, including a spreadsheet program called Calc and a presentation program called Impress, whereas Microsoft Office has Excel and PowerPoint. Ultimately, the choice between the two suites will depend on your specific needs and preferences.