The Río Rosario is a river of Maricao, Hormigueros, San Germán and Mayagüez in Puerto Rico.

Skirmishes were fought here during the Spanish-American War.

See also

• Maricao Fish Hatchery: located along the river in Maricao, Puerto Rico
• Torréns Bridge: crosses the river in Hormigueros, Puerto Rico
• List of rivers of Puerto Rico