HFS Plus，或HFS+是苹果公司为替代他们的分层文档系统（HFS）而开发的一种文档系统。它被用在macintosh电脑（或者其他运行Mac OS的电脑）上。它也是iPod上使用的其中一种格式。HFS+也被称为OS X Extended（或误称为“HFS Extended”）。在开发过程中，苹果公司也把这个文档系统的代号命名为“Sequoia”。

HFS+是一个HFS的改进版本，支持更大的文档，并用Unicode来命名文档或文档夹，代替了Mac OS Roman或其他一些字符集。 和HFS一样，HFS+也使用B树来存储大部分分卷元数据。

HFS Plus or HFS+ is a proprietary file system developed by Apple Inc. It serves as the primary file system of OS X. HFS+ was developed to replace the Hierarchical File System (HFS) as the primary file system used in Macintosh computers (or other systems running Mac OS). It is also one of the formats used by the iPod digital music player. HFS Plus is also referred to as Mac OS Extended (or, erroneously, "HFS Extended"), where its predecessor, HFS, is also referred to as Mac OS Standard (or, erroneously, as "HFS Standard"). During development, Apple referred to this file system with the codename Sequoia.