Yes, OS X is UNIX. Apple has submitted OS X for certification (and received it,) every version since 10.5. However, versions prior to 10.5 (as with many ‘UNIX-like’ OSes such as many distributions of Linux,) could probably have passed certification had they applied for it.

Is Mac a UNIX or Linux?

macOS is a series of proprietary graphical operating systems which is provided by Apple Incorporation. It was earlier known as Mac OS X and later OS X. It is specifically designed for Apple mac computers. It is based on Unix operating system.

Is Linux a type of Unix?

Linux is a UNIX-like operating system. The Linux trademark is owned by Linus Torvalds.