A "leaf peeper", or "leafer", is the New England regional slang term for a person, usually a tourist, who drives very slowly throughout the north-east portion of the United States during autumn while looking out the windows of their car at the annual foliage color change. The act performed by leaf peepers is also known as leaf peeping. New England fall foliage is a major tourist attraction for the area, with vibrant red, yellow and orange colors appearing on the deciduous trees after the first snap frosts.

The term gained national attention on the Family Guy episode "Lethal Weapons", where a bunch of obnoxious leafers, particularly from New York, invade the town.