ReiserFS，是一种文档系统格式，作者是汉斯·瑞塞尔（Hans Reiser）及其团队Namesys，1997年7月23日他将ReiserFS文档系统在互联网上公布。Linux内核从2.4.1版本开始支持ReiserFS。

ReiserFS的命名是源自作者Hans Reiser的姓氏，这个日志型文件系统发展比ext2/3晚近许多。在技术上使用的是B*-tree为基础的文件系统，其特色为能很有效率地处理大型文件到众多小文件都可以用很高的效率处理；实务上ReiserFS在处理文件小于1k小文件时，甚至效率可以比ext3快约10倍。

ReiserFS is a general-purpose, journaled computer file system formerly designed and implemented by a team at Namesys led by Hans Reiser. ReiserFS is currently supported on Linux (without quota support). Introduced in version 2.4.1 of the Linux kernel, it was the first journaling file system to be included in the standard kernel. ReiserFS is the default file system on the Elive, Xandros, Linspire, GoboLinux, and Yoper Linux distributions. ReiserFS was the default file system in Novell's SUSE Linux Enterprise until Novell decided to move to ext3 on October 12, 2006 for future releases.