Gamma Squadron was a millitary unit of the Terran Confederacy, consisting of multiple Divisions. Many members of the Marine Corps are former criminals Its function is not clearly described but it appears to take on more mundane tasks than its counterpart squadrons, such as guarding establishments and settling claim disputes. Its colour is unknown.
A Gamma Squadron force was stationed on Vyctor 5 at a Confederate facility situated within the Fujita Pinnacle for over a month, guarding scientists studying recently discovered xenomorphs, a fact which caught the attention of the newly formed Sons of Korhal. At the time of the attack, the unit was about to be replaced, set to "go back to forcibly settling claim disputes and ridding the miners' daughters of their pesky virginity" (at least in the mind of Gunnery Sergeant Mitch Tanner). Despite a stuborn defence the base was overrun and most, if not all of the unit wiped out.
Gamma Squadron's fate in the aftermath of the fall of the Confederacy is unknown. However, there is evidence that it may have joined, willingly or unwillingly, with the United Earth Directorate Expeditionary Force, the two factions sharing a common enemy in the Terran Dominion. This is backed up in that Valkyries were among the Squadron. However, the force was wiped out by Infested Kerrigan's Zerg and presumably any members of Gamma Squadron which may have joined it. However, a few members may be among those in a UED base on Abaddon.