A rain gutter (also known as eaves trough, eaves channe guttering or simply as a gutter) is a narrow channel, or trough, forming the component of a roof system which collects and diverts rainwater shed by the roof.

The main purpose of a rain gutter is to protect a building's foundation by channeling water away from its base. They also help to reduce erosion, prevent leaks in basements and crawlspaces, protect painted surfaces by reducing exposure to water and provide a means to collect rainwater for later use.