The Leaning Pine Arboretum (2 ha / 5 acres) is an arboretum and botanical garden located at the north end of the California Polytechnic State University campus in San Luis Obispo, California. It is open to the public, free, during working hours from Monday through Saturday. It contains hundreds of plants from the world's five Mediterranean climate regions, along with collections of palms, aloes and other succulents, dwarf, and unusual conifers, and New Zealand plants.

Its collections are organized as the Arboretum, Display Garden, Native Plant Garden, Research Garden, and Xeriscape Garden. New gardens feature South African and Australian plants, and a Chilean garden is in the development stage.