Mighty Jack (マイティジャック, Maiti Jakku) is a tokusatsu science fiction/espionage/action TV series. Created by Japanese effects wizard Eiji Tsuburaya, the show was produced by Tsuburaya Productions and was broadcast on Fuji TV from April 6, 1968 to June 29, 1968, with a total of 13 one-hour episodes. The music for the episodes was done by Isao Tomita and Kunio Miyauchi.

Reportedly, Eiji Tsuburaya considered this series his masterwork because the focus was on the people, rather than on the vehicles and special effects (the show never had any monsters or aliens, as his more famous shows Ultra Q, Ultraman and Ultra Seven did). This focus on the people was similar to the works of Gerry Anderson, of which Tsuburaya was a big fan. The Mighty Jack mecha/HQ featured in this series also has some similarities to Tsuburaya's previous TV masterpiece, Ultra Seven.

Even for the original series of 13 one hour-long episodes, the ratings were low. The follow-up series, Fight! Mighty Jack, fared better in the ratings, perhaps because of its inclusion of monsters and aliens, rather than purely human evildoers like Q.

The insignia of the titular heroic spy team has also become the current logo for Tsuburaya Productions.