The Río Paz (Spanish pronunciation: [ˈri.o pas]) is a river in southern Guatemala. Its sources are located in the Quezalapa mountains in the north of Jutiapa. From there it flows in a south-westerly direction and marks the border with El Salvador for most of its course before reaching the Pacific Ocean at 13°46′16″N 90°10′57″W / 13.77111°N 90.18250°W / 13.77111; -90.18250 (Mouth of the Río Paz).

The Paz River is 134 kilometres (83 mi) long, and its basin covers a territory of 1,732 square kilometres (669 sq mi) in Guatemala.

It flows through the Ahuachapán Department and into the Laguna el Espino.