The MSZ-010 ΖΖ Gundam (aka ΖΖ Gundam, ZZ; pronounced "Double Zeta") is the titular mobile suit of the anime Mobile Suit Gundam ZZ and is piloted by Judau Ashta.

A direct development of the MSZ-006 Zeta Gundam, the ΖΖ Gundam, which had been completed through a prototype, was given the development code "θ" (thus also known as the "θ Gundam") as it was the sixth "Anaheim Gundam" after the RMS-099 Rick Dias (also known as “γ Gundam”). The development plan of the ΖΖ Gundam existed two years before the completion of the Zeta Gundam but was shelved due to internal competition and production delays. However, the performance advantage of the Zeta Gundam against new Titans mobile suits did not last long, and so development of the ΖΖ Gundam was resumed.

The ΖΖ Gundam sought to reproduce the operating functions of the RX-78-2 Gundam and the G-Armor in a single machine. An advanced form of the RX-78-2 Gundam's Core Block System was also introduced. As a result, the ΖΖ Gundam can transform into a mobile armor form called the G-Fortress, which acts as a heavy combat bomber and for cruising in space and on earth. The ΖΖ Gundam can also separate into two independent fighter units, called the Core Top and Core Base. The Core Base, consisting of the ΖΖ's lower body and backpack, is operated through the FXA-07GB Neo Core Fighter attached to its front. The Core Top, consisting of the ΖΖ's upper body and double beam rifle, is operated through the cockpit in its nose unit or more frequently through the Neo Core Fighter, which is in its Core Block form, attached to the lower rear.

The team on board the "Argama" typically operates the ΖΖ Gundam with a third Neo Core Fighter piloted by the Gundam's main pilot, Judau Ashta. When combining into the ΖΖ Gundam, forming the G-Fortress mode is the first step and consists of the Core Top and Core Base ejecting their Neo Core Fighters to dock with Judau's Neo Core Fighter in Core Block form. When transforming from the G-Fortress mode to MS mode, the large verniers in the arms and legs are retracted. However, this does not reduce total thrust as the surplus output is supplied to the attitude control thrusters distributed throughout the body and the number of operable thrusters are actually increased. Other parts that move during transformation include the flexible wing binders that also serve as arm-mounted wings shields, the shoulder thruster binders, the large backpack, etc.

The engine installed in the backpack is originally meant for ships and could supply power for an entire ship. It also functions as the main thruster unit of the ΖΖ Gundam when in MS form, generating thrust equivalent to that of a large ship. The ΖΖ Gundam's armor is a multi-spaced structure composed of Gundarium γ alloy, capable of withstanding a mobile suit explosion at close range and resisting high water pressure. While it is impossible to completely defend against a direct hit of a mega particle beam, the wings shields are strong enough to prevent a direct hit on the cockpit.

With its overall height limited to around 20 meters as requested by AEUG to maintain mobility, the ΖΖ Gundam's design also incorporated the movable frame and magnet coating technology. The generator output which had caused problems during early stages of ΖΖ's development was resolved by incorporating three compact, high-output generators. The movable modules and armor parts, which have a multi-layered structure, are connected by hinges and slide rails which have magnet coating, making them flexible and robust while allowing instantaneous transformation of the ΖΖ Gundam. However, the complexity of the system resulted in poor maintainability and productivity also deteriorated.

The control system of the ΖΖ Gundam is equipped with a Bio-Sensor, which is a simplified Psycommu system, as an interface for Newtype pilots. An improved version of the Biosensor installed in the Zeta Gundam, it improves the responsiveness of the mobile suit by supporting the control system with the pilot's brainwaves. However, as a protective measure, the Biosensor is inactive when a pilot with low Newtype abilities boards the ΖΖ Gundam. The unit is mounted in the ΖΖ Gundam's Core Block and the synchronization of the device is improved by inputting the brainwave patterns of the Neo Core Fighter's pilot.

The ΖΖ Gundam has a number of powerful weaponry, including two hyper beam sabers which are also usable as beam cannons, a double beam rifle, a 21-tube missile launcher installed on the backpack, and a high mega cannon on the forehead. While the ΖΖ has a very destructive arsenal, its weapons systems require a high level of energy. As a result, the ΖΖ often found itself almost completely drained of power after using its high mega cannon. The ΖΖ Gundam's structural issues due to its complicated construction and transformation systems were eventually corrected with the MSZ-010S Enhanced ZZ Gundam and its massive final upgrade FA-010S Full Armor ZZ Gundam.