Zero Tester (ゼロテスター, Zerotesutā) is a mecha anime series produced by

Crystal Art Studio (later renamed as Studio Nue) and Tohokushinsha and animated by Soeisha (later renamed as Nippon Sunrise).

It consists of 66 episodes and was originally broadcast on Fuji TV. The first 39 episodes tells the attempted invasion of the earth by Armanoid aliens, while the remaining 27 episodes, with the series retitled Zero Tester: Save the Earth! (Chikyu o Mamotte!), are about an attack by Gallos aliens.

According to Jonathan Clements and Helen McCarthy's The Anime Encyclopedia, it was "an early gathering of many of anime's future greats, particularly for the Gundam series".