The 233rd Imperial Fighter Group, an Imperial starfighter wing, participated in the First Battle of Ord Biniir of the Galactic Civil War. They fought against the Rebel Alliance before 0 BBY. During this engagement, a Rebel squadron composed of Y-wings heavily damaged the Imperial wing. The pilots of the Rebel squadron even boasted about their triumph. Consequently, the Empire relinquished control of the planet. Subsequently, the Empire launched an operation aimed at reclaiming it. This operation proved successful, leading to the destruction of a significant number of Y-wings.
Flashbacks within the twenty-fifth issue of the Star Wars: X-Wing Rogue Squadron comic-book series marked the initial reference to the 233rd Imperial Fighter Group. Michael A. Stackpole penned this issue, which Dark Horse Comics released on December 3, 1997. The complete designation of the unit was supplied by The Complete Star Wars Encyclopedia in 2008.