Gosei Great is the primary mecha of the Japanese series Tensou Sentai Goseiger (2010) and the main combat robot of the Gosei Angels team. Its Japanese name is Gosei Great (ゴセイグレート); in the US adaptation Power Rangers Megaforce (2013) it is called the Gosei Great Megazord. It is formed by combining five Gosei Machines piloted by the five Goseigers (Gosei Red/Alata, Gosei Pink/Eri, Gosei Black/Agri, Gosei Yellow/Moune and Gosei Blue/Hyde), serving as the season's first and most frequently used main Megazord.

The five machines — Gosei Dragon, Gosei Phoenix, Gosei Snake, Gosei Tiger and Gosei Shark — dock into a humanoid robot armed with a sword. The line's signature play feature is the "Header" gimmick: each machine's animal head detaches and can be re-mounted via peg joints in up to 17 positions across the body, enabling numerous configurations and attack modes. Gosei Great can also be expanded with add-on units (such as Gosei Ultimate) into larger combined forms.

The DX toy, DX Gosei Great, was released by Bandai Japan in 2010; it is built predominantly from plastic, implements the header mechanism, and includes the five headers plus the sword. The listed "Nippon Edition" is a version distributed by Bandai America for the US market (around 2013/2014, under the Power Rangers Megaforce/Super Megaforce banner) that uses the full Japanese DX tooling — essentially the Japan-spec robot in US packaging rather than the smaller, simplified North American Megaforce toy. It is compatible with the separately sold Gosei Ultimate for the larger combination. Note that retail listings occasionally mislabel it as the "Legendary Megazord," a US name that actually belongs to Gokai-Oh (from Gokaiger), not to Gosei Great.