System is a family of proportional raster fonts distributed with Microsoft Windows.

[1] Sharing the same letterforms as Microsoft Sans Serif which in turn is modeled after Helvetica, the font family contains fonts encoded in several Windows code pages, with multiple resolutions of the font for each code page.

Similarly, changing language setting for Windows applications that do not support Unicode will alter the appearance of the font.

The copyright message in the .FON file says the font was designed by Microsoft Corporation in 1988–1989.

Microsoft also created CGA, EGA and 8514/A versions of the font.