|First appearance||Super Mario Galaxy 2 (2010)|
|Number of Stars||2|
The Grandmaster Galaxy is a galaxy in Super Mario Galaxy 2. It is the last galaxy to be unlocked in the game The galaxy is located in World S. This galaxy is unlocked when Mario gets all 120 Power Stars and all 120 secret Green Power Stars, similar to the Grand Finale Galaxy in Super Mario Galaxy. It is an obstacle course with puzzles and enemies. The galaxy is divided into six sections, each presenting a different challenge to the player.
- The first section is where you swing from flower to flower with Yoshi's tongue, while avoiding mines, Bullet Bills, and Paragoombas. Choppahs replace the paragoombas in the galaxy's comet mission.
- The second section is a square of Flipswitches. The player must activate them all before the Launch Star appears while avoiding Sentry Beam attacks.
- The third section is a maze of electric bolts that the player must maneuver around via Cloud Flower. The player will have to let go of Yoshi in this part if he/she has not already done so.
This galaxy contains two Stars: one for completing the level and another one for doing it again under Daredevil Comet conditions. In the latter case Mario gets the Star from Rosalina. They should be the 241st and 242nd stars in the game