The RX-178+FXA-05D Super Gundam is a mobile suit introduced in the anime Mobile Suit Zeta Gundam. Piloted by Emma Sheen, it is the combination of the FXA-05D G-Defenser and the RX-178 Gundam Mk-II.

To increase the RX-178 Gundam Mk-II's combat capabilities to match those of the Titans' transformable mobile suits, Anaheim Electronics developed the FXA-05D G-Defenser support fighter, which can dock and power up the Gundam Mk-II. This combined form is technically known as the 'Mk-II Defenser', but is more commonly called the Super Gundam due to its performance.

The Super Gundam is only formed after the G-Defenser and Mk-II are launched. During the docking process, the entire G-Defenser first docks with the Mk-II, forming the G-Flyer mode which is a high-speed, long distance travelling form that has the same level of acceleration as a transformable mobile suit. The G-Defenser's cockpit capsule then detaches, leaving the support craft's body attached to the Mk-II, completing the formation of the Super Gundam.

The Super Gundam improves the Mk-II's mobility by roughly 20% thanks to G-Defenser's powerful thrusters, and the G-Defenser's armament units become movable shields to protect the mobile suit. The Mk-II also gains the use of the G-Defenser's powerful long rifle and missile pods while retaining several of its own armaments. However, the Mk-II's shield must be discarded to allow space for the docking procedure.