The Ambush at Mon Calamari, also known as the Attack on Mon Calamari, was a battle that occurred in 1 BBY. During the early Galactic Civil War, Palpatine believed that the Mon Calamari would likely try to join the growing Rebel Alliance. In order to prevent this, a raid was organized against the shipyard.
Despite the fact that Imperials had already attacked Mon Calamari, the emperor believed that sooner or later, the species would attempt to join the growing rebel movement. Furthermore, the species was building more capital ships. If the Mon Calamari Orbital Shipyards joined the Rebellion, the Alliance Fleet would be able to compete with Imperial Star Destroyers.
Coming out of hyperspace, the Imperials proclaimed that the planet was under the control of the Empire. However a large force of Rebels, supported by a space station, attacked the invading fleet. The Imperials began to move against the Rebels.
The Imperial Navy focused on the space station, taking out the hanger and many weapon emplacements. despite being hammered by the rest of the enemy fleet, the Empire's navy began to take the upper hand.
However, two completed Mon Cal Star Cruisers arrived to out flank the Imperials. Finishing off the space station, the imperial fleet engaged the two capital ships. Despite heavy casualties, reinforcements continued to arrive, and the MC80 cruisers were destroyed. The remaining Imperial ships destroyed the enemy survivors.
The Imperial fleet captured numerous free Mon Calamari for use as slave labor. Meanwhile, the fleet annexed plans for new starships and placed them in a base on Carida.
However, the planet would only remain in the empire's control for so long. The annexed plans were recaptured, and the next imperial counterattack would fail.
This battle was the fifth mission of the Imperial campaign in the 2006 video game Star Wars: Empire at War.