符号链接（软链接）是一类特殊的文档， 其包含有一条以绝对路径或者相对路径的形式指向其它文档或者目录的引用。 符号链接最早在4.2BSD版本中出现（1983年）。今天POSIX操作系统标准、大多数类Unix系统、Windows Vista、Windows 7都支持符号链接。Windows 2000与Windows XP在某种程度上也支持符号链接。

符号链接的操作是透明的：对符号链接文档进行读写的进程会表现得直接对目标文档进行操作。某些需要特别处理符号链接的进程（如备份进程）可能会识别并直接对其进行操作。

In computing, a symbolic link (also symlink or soft link) is the nickname for any file that contains a reference to another file or directory in the form of an absolute or relative path and that affects pathname resolution.

Symbolic links were already present by 1978 in minicomputer operating systems from DEC and Data General's RDOS. Today they are supported by the POSIX operating system standard, most Unix-like operating systems such as FreeBSD, GNU/Linux, and Mac OS X and Windows operating systems such as Windows 95, Windows Vista, Windows 7 and to some degree in Windows 2000 and Windows XP in the form of Shortcut files.