San Mateo Arboretum, Botanical garden in San Mateo, United States.

San Mateo Arboretum is a botanical garden within Central Park containing sections of pine, oak, cedar, and coast redwood trees spread across multiple acres. The site also includes an adjacent Japanese tea garden with traditional design elements that adds another dimension to the overall landscape.

John McLaren planted the original collection of trees over 100 years ago on the William Kohl estate, establishing the foundation for what exists today. This early planting effort later grew into an organized effort to maintain and expand the garden.

The San Mateo Arboretum Society, founded in 1975 by Marion Panaretos, is a volunteer-run nonprofit with more than 200 members. Volunteers tend the rose garden, plant nurseries and native plant garden, and the rose garden is often chosen for weddings. The society also hosts horticultural classes and events and sells propagated plants from its greenhouse.

The arboretum lies within San Mateo's Central Park, with the Arboretum Society based near the Kohl Pump House; the address given is 101 9th Avenue. Entry is free. The Society's volunteers tend the rose garden, plant nurseries and native plant garden, and the greenhouse propagates plants, some of which are sold to the public.

The Japanese tea garden was designed by Nagao Sakurai and reflects the sister-city relationship between San Mateo and Toyonaka, Japan. Many visitors overlook this design feature, but those who find it consider it a special hidden element of the grounds.