Thief has snuck stealthily onto Mac OS X, ported by Feral Interactive.

Loot the informative documents from the Mac version minisite then find Thief: Master Thief Edition stashed here on Steam with the additional bounty of a mini digital art book, comic book and soundtrack. Playable DLC is available separately.

The system requirements are:

MINIMUM:
OS: Mac OS X 10.10.5
Processor: 1.8 GHz Intel
RAM: 4GB
Hard Disk: 35GB
Graphics: 1GB
Input: Keyboard & Mouse

RECOMMENDED:
OS: Mac OS X 10.11.1 or higher
Processor: 2.4 GHz Intel
RAM: 8GB
Hard Disk: 45GB
Graphics: 2GB
Input: Gamepad

The following graphics cards are not supported: AMD Radeon HD 4xxx series, ATI X1xxx series, ATI HD2xxx series, Intel Iris 5100, Intel HD5000, Intel Iris 6100, Intel HD6000, Intel HD5300, Intel GMA series, Intel HD3000, Intel HD4000, NVIDIA 1xx series, NVIDIA 9xxx series, NVIDIA 8xxx series, NVIDIA 7xxx series and NVIDIA 3xx series.

This game is not currently supported on volumes formatted as Case-sensitive.