The First Battle of Geonosis, also referred to as the Battle of Geonosis or the Battle on Geonosis, was the first major battle fought in 22 BBY between the Confederacy of Independent Systems and the Galactic Republic on Geonosis, marking the beginning of the three-year Clone Wars. It would be the first major combat of the Grand Army of the Republic, as well as the first major battle the Jedi had fought in years. The battle also caused the death of the notorious bounty hunter Jango Fett and the discovery of Count Dooku‘s dark side allegiance.

The First Battle of Geonosis first appeared in the 2002 film Star Wars: Episode II Attack of the Clones, the second installment of the Star Warsprequel trilogy. The 2016 reference book Star Wars: Complete Locations establishes that the Republic was outnumbered by the Separatist Army by giving the number of troops each side used. A later reference book, 2017‘s Star Wars: On the Front Lines, stated that the Republic held the numerical advantage. Because Complete Locations gives official troop numbers, this article assumes it is correct.