Leaf peeping is an informal term used in the United States and Canada for the activity of traveling to view and photograph the fall foliage in areas where leaves change colors in autumn, particularly in northern New England, Appalachia, the Pacific Northwest, and the upper Midwest, as well as the provinces of Ontario and Quebec. The term "leaf peeper" is used both with appreciation from businesses that benefit from the millions that pour into the higher elevations of the West, upper Midwest, and northern New England in fall, and with disdain from those who have to use the roads that get over-crowded due to leaf peepers. An organized excursion for leaf peeping is known as a foliage tour or color tour. In Japan, a similar custom is called momijigari, and in Finland, the season is ruska, and a trek is called ruskaretki.

The term "leaf peeping" may stem from a Vermont term, "leaf-peeker" from the early 1900s. The popular autumn activity of admiring the changing colors of leaves—via a road trip, a hike in a forest, or simply a stroll through a park—signals an appreciation of nature. The term "peep" in leaf peeping is slang for seeing or watching, but theres the lurking connotation of “Peeping Tom,” which since the late 18th century has been another name for a voyeur.

Leaf peeping is a very popular recreational activity in national parks during the autumn months. The National Park Service recommends being aware of your surroundings and following safety tips when viewing fall colors, such as keeping your distance from drop-offs, finding a safe place to take photos, and watching the road.

In summary, leaf peeping is an activity of traveling to view and photograph the changing colors of fall foliage during the autumn months, particularly in certain regions of the United States and Canada. It is a popular recreational activity that signals an appreciation of nature, and it can be enjoyed through a road trip, a hike in a forest, or simply a stroll through a park.