安全增强式Linux（SELinux, Security-Enhanced Linux）是一种强制访问控制（mandatory access control）的实现。它的作法是以最小权限原则（principle of least privilege）为基础，在Linux核心中使用Linux安全模块（Linux Security Modules）。它并非一个Linux发行版，而是一组可以套用在类Unix操作系统（如Linux、BSD等）的修改。

Security-Enhanced Linux (SELinux) is a Linux kernel security module that provides a mechanism for supporting access control security policies, including United States Department of Defense–style mandatory access controls (MAC).

SELinux is a set of kernel modifications and user-space tools that have been added to various Linux distributions. Its architecture strives to separate enforcement of security decisions from the security policy itself and streamlines the volume of software charged with security policy enforcement. The key concepts underlying SELinux can be traced to several earlier projects by the United States National Security Agency.