KiriKiri (吉里吉里, KiriKiri?) is a scripting engine by Japanese developer "W.Dee". It is almost exclusively used with the KAG (KiriKiri Adventure Game System) framework to produce visual novels. Usually, the package of the two components is regarded as the whole engine, and referenced with major version numbers.Therefore, the current version is called KiriKiri2/KAG3. It is available under the GNU General Public License, though commercial licenses can be acquired if somebody wishes to expand the software without disclosing the changes.

KiriKiri has been used in both dōjin and commercial visual novels, the most well known of which are TYPE-MOON's Fate/stay night and Fate/hollow ataraxia. It is often used as a more modern and expandable replacement of the older NScripter engine.

KiriKiri stores its resources in archives with the .xp3 extension, though those archives can be concatenated with the executable for simple distribution as well. A further file format associated with KiriKiri is .tlg, a bitmap image file format with an integrated alpha channel. The scripting language itself (called TJS) is reminiscent of the object-oriented languages derived from ECMAScript (for example JavaScript), and KAG implements a tag-based markup formatting system similar to XML. KiriKiri/KAG is expandable with plugins in both binary (.dll) or its own script format. Though the engine is open-source, it has as of yet not been ported to operating systems other than Microsoft Windows, and more specifically Windows with Japanese language settings. To run nearly all KiriKiri-based games, it is necessary to either set the Windows locale to Japanese or to use AppLocale in Japanese mode. It is not necessary to set the Windows locale to Japanese or to use AppLocale in Japanese mode now if KiriKiri-based games use Unicode character set.