Dai-Guard (地球防衛企業 ダイ・ガード, Chikyū Bōei Kigyō Dai Gādo, lit. "Terrestrial Defense Corp. Dai-Guard") is an anime television series, produced and animated by XEBEC, and directed by Seiji Mizushima. It aired from October 5, 1999, to March 28, 2000, on TV Tokyo, running for 26 episodes. 6 volumes of videos were released on VHS and DVD. The series also had a very brief run (two episodes) on Cartoon Network through Toonami's "Giant Robot Week".

The series is based around three office workers of the 21st Century Defense Security Corporation's Public Relations Division 2 who, with the company's giant robot, Dai-Guard, fight interdimensional alien beings called "Heterodynes". Unlike most giant robot anime, Dai-Guard performs on much more realistic physics, making it heavy, slow, and difficult to control. Also, the Heterodynes seem to be the least of the 21st Century Corporation's problems as they experience opposition in the form of massive damage claims, lawsuits, rivals and a jealous and antagonistic military who wishes to take back Dai-Guard for themselves.