Assuming OS X is an Apple platform operating system, if you go far enough back, yes. Most of Apple's current Operating System evolved from Unix, which is the grandfather to both Apple's macOS and the modern forks of Linux.
macOS has it's own list of Steam compatible games (mostly because of limiting the use of older, less secure 32 bit executable) but it's a lot more of an option now than it was even 5 years ago.
https://store.steampowered.com/macos
About the only platform that can't do Steam now is Google ChromeFlexOS.