MIT許可證

简介

MIT许可协议之名源自麻省理工学院（Massachusetts Institute of Technology, MIT），又称“X许可协议”（X License）或“X11许可协议”（X11 License）
MIT内容与三条款BSD许可协议（3-clause BSD license）内容颇为近似，但是赋予软件被许可人更大的权利与更少的限制。

运用情形

有许多团体均采用MIT许可证。例如著名的SSH连线软件PuTTY与X窗口系统。Expat、Mono开发平台库、Ruby on Rails、Lua等等也都采用MIT许可协议。

条款内容

普遍的MIT协议声明原文如下： 
Copyright (C) <year> <copyright holders>

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
中文解释如下：

被许可人权利

被许可人有权利使用、复制、修改、合并、出版发行、散布、再许可和/或贩售软件及软件的副本，及授予被供应人同等权利，惟服从以下义务。

被许可人义务

在软件和软件的所有副本中都必须包含以上著作权声明和本许可声明。

其他重要特性

此许可协议并非属copyleft的自由软件许可协议条款，允许在自由及开放源代码软件或非自由软件（proprietary software）所使用。 
MIT的内容可依照程序著作权者的需求更改内容。此亦为MIT与BSD（The BSD license, 3-clause BSD license）本质上不同处。 
MIT许可协议可与其他许可协议并存。另外，MIT条款也是自由软件基金会（FSF）所认可的自由软件许可协议条款，与GPL兼容。