Masters-at-Arms are non-commissioned officers responsible for internal security aboard Colonial warships, including battlestars. Within their policing capacity, they are charged with law enforcement duties such as conducting criminal investigations and inquiries (TRS: "Act of Contrition"). Galactica's Master-at-Arms is Sergeant Hadrian.
- Master-at-Arms (MAA) is a naval term relating to a petty officer aboard ship assigned to maintaining discipline.
- Within the US Navy, larger vessels may have a number of MAAs, with the most senior being the Chief Master-at-Arms (CMAA), referred to as the "Sheriff".
- Within the Royal Navy, the MAA is supported by a ship's Corporal-at-Arms.