ZenkaiOh JuraGaon (ゼンカイオー ジュラガオン) is the first and central robot combination from the series Kikai Sentai Zenkaiger (2021). The Zenkaiger team consists of the human leader Zenkaizer and four robotic Kikainoid partners; ZenkaiOh JuraGaon is formed from two of them: Zenkai Juran (the red ranger, with a Tyrannosaurus motif paying homage to Kyoryu Sentai Zyuranger) and Zenkai Gaon (a lion motif paying homage to Hyakujuu Sentai Gaoranger). As the show's debut mecha, JuraGaon serves as the primary battle robot from the outset.

The Kikainoids are themselves robots that grow to combat size in order to unite. ZenkaiOh follows a left/right modular principle: in JuraGaon, the T-Rex robot Juran forms one body half (one arm and one leg) and the lion robot Gaon the other. The mecha is controlled by one of the two by snapping the fangs — once for Juran, twice for Gaon — and is armed with the Juran Sword and Juran Shield under Juran's control, or the Gaon Claw under Gaon's. "ZenkaiOh" is the umbrella name for the combination, and the suffix combines the names of both partners (Juran + Gaon). Using the same principle, the four Kikainoids can be freely combined into further ZenkaiOh forms, such as ZenkaiOh JuraMagine (Juran + Magine) or ZenkaiOh JuraVroon (Juran + Vroon).

As a DX toy, ZenkaiOh JuraGaon is made by Bandai (Japan) and was released in 2021 as the "Zenkai Gattai DX ZenkaiOh JuraGaon" set, which contains the two DX robots Juran and Gaon that plug together to form the combination (first released 6 March 2021). Both are made largely of plastic (ABS/PVC), are playable in their individual forms, and are modular and interchangeable, enabling the various ZenkaiOh combinations. Because Kikai Sentai Zenkaiger was never adapted into a Power Rangers season, no corresponding US toy exists — ZenkaiOh JuraGaon is available solely as a Japanese Bandai DX import.