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 (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.