Brownwater Navy is a term in American naval speech referring to actions in near shore and riverine enviroments. Small gunboats and patrol craft are the ships used by a brownwater force. World War II PT boats and the interwar river gunboats are forerunners of the concept. The Littoral Combat Ship may have be brown water capable, and Naval War College Wargaming has shown the effectiveness of the idea. Sen. John Kerry of Massachusetts has made his service in the Vietnam era brownwater navy a center piece of his 2004 Presidental campaign.

"Brownwater" is used to differentiate these ideas from the preferred large, ocean going craft preferred by the Navy.