TeXShop is a free LaTeX and TeX editor and previewer for Mac OS X. It is licensed under the GNU GPL.It was developed by the American mathematician Richard Koch. TeXShop was modeled on NeXTstep's bundled TeXview.app and developed for the then new Mac OS X user interface Aqua and capitalized on the native PDF support of that version of the Macintosh operating system, which was itself based on NeXTstep's successor OpenStep.