The Temporal Mechanics Department is an organization within the United Federation of Planets, responsible for the study of time travel.

In 2404 of an alternate timeline, Commander Reginald Barclay and Admiral Kathryn Janeway were giving a lecture on the Borg at Starfleet Academy. One Cadet had a question for Janeway, but thought it could wait until after the class had ended. Janeway responded, "as they say in the Temporal Mechanics Department, there's no time like the present." (VOY: "Endgame")