Knol 是Google公司的一个计划，目的是要创建一个类似维基百科或大众百科（Citizendium）的网站，让网友可参与编写知识性内容。「Knol」是 Google 自创的新词，取自 Knowledge（知识），是「一个知识单位」的意思（A unit of knowledge）。每一篇文章亦可以用 Knol 来称呼。此计划于2007年12月13日发表，在内部测试期间，与 Gmail 初期一样，需要以邀请的方式才可加入；于2008年7月23日，Knol 完全开放给大众使用。其平台采用Solvitor和Crowd Favorite创建的基于Wordpress的Annotum。

Knol was a Google project that aimed to include user-written articles on a range of topics. Lower-case, the term knol, which Google defined as a "unit of knowledge", referred to an article in the project.

The project was led by Udi Manber, a Google vice president of engineering. It was announced on December 13, 2007, and was opened in beta version on July 23, 2008, with a few hundred articles, mostly in the health and medical field. The project was closed on April 30, 2012, and all content was deleted by October 1, 2012. The Internet Archive has snapshots of knol archived between July 2008 and May 2012.