The Mrs. Oakleigh Thorne Medal is awarded for outstanding achievement in design, architecture, or art related to the garden.

The Mrs. Oakleigh Thorne Medal was designed in 1954 by Maude Robinson and endowed by the Millbrook Garden Club, Zone III, in memory of member and GCA founder Helen Seymour Stafford Thorne (1866–1952) who was also a member of The Garden Club of Santa Barbara, Zone XII. She was chair of the Visiting Gardens Committee for 20 years, and designed public and private gardens of distinction and rare beauty in the New York and California communities in which she lived. She received the Frances K. Hutchinson Medal in 1940 for her work to preserve California’s redwoods. The medal was designed in 1954 by Maude Robinson and first awarded in 1956.