The Adeptus Mechanicus is the offical name for the Cult Mechanicus or Cult of the Machine in the Warhammer 40,000 universe. They acknowledge the Emperor as the ruler of the Imperium, but not the Imperial Cult or the Ecclesiarchy. Instead they follow their own dark and mysterious strictures.

They believe knowledge is the manifestation of divinity, and all creatures and artefacts that embody knowledge are holy because of it. The Emperor is the supreme object of worships because he comprehends so much.

The Adpetus Mechanicus is based on Mars and are the sole rulers of that planet. They provide the technical experts of the Imperium and field armies of Titans and Knights.