OpenBSD是一个类Unix计算机操作系统，是加州大学伯克利分校所开发的Unix衍生系统伯克利软件套件（BSD）的一个后继者。它是在1995年尾由项目领导者西奥·德·若特从NetBSD分支而出。除了操作系统，OpenBSD项目已为众多子系统编写了可移植版本，其中最值得注意的是PF、OpenSSH和OpenNTPD，作为软件包，它们在其他操作系统中随处可见。

该计划以其对开放源代码的坚持、高质量的文档、坚定的软件许可证和专注于系统安全及代码质量而闻名。该项目由德·若特在加拿大阿尔伯塔省卡尔加里的家中所协调。它的标志和吉祥物是一只河豚，名为普菲（Puffy）。

OpenBSD is a Unix-like computer operating system descended from Berkeley Software Distribution (BSD), a Research Unix derivative developed at the University of California, Berkeley. It was forked from NetBSD by project leader Theo de Raadt in late 1995. As well as the operating system, the OpenBSD Project has produced portable versions of numerous subsystems, most notably PF, OpenSSH and OpenNTPD, which are very widely available as packages in other operating systems.