Aldnoah.Zero (Japanese: アルドノア・ゼロ, Hepburn: Arudonoa Zero, stylized in logo as ΛLDNOΛH.ZERO) is a television and print series created by Olympus Knights and A-1 Pictures. It presents the fictional story of the Vers Empire's 37 clans of Orbital Knights' attempted reconquest of Earth—enabled by the empowering titular Aldnoah energy/drive technology—following return to Earth as a more technologically advanced people after a human diaspora to the planet Mars.

Plotted by Gen Urobuchi with direction by Ei Aoki, the series features principal Japanese voice acting by Natsuki Hanae, Sora Amamiya and Kensho Ono, with animated relational and battle scenes set on or in the orbit of the fictional Earth of 2014, the Landing Castles of the Vers Empire's Orbital Knights, Vers bases on a shattered remnant of Earth's Moon, and occasionally, the Vers palace of its failing emperor on Mars. The series began in July 2014, and as of March 2015, had presented two 12-episode seasons, with Urobuchi, Katsuhiko Takayama and Shinsuke Onishi, and then Hiroyuki Sawano and Kalafina, respectively, receiving principal script-writing and music credits.