Ventnor Botanic Garden is a botanic garden located in Ventnor, Isle of Wight. It was founded in 1970, by Sir Harold Hillier, and donated to the Isle of Wight Council. The garden is free to visit, except for parking charges.

Its collection comprises worldwide temperate and subtropical trees and shrubs organised by region. These grow in the open air, the location favoured by the moist and sheltered microclimate of the south-facing Undercliff landslip area on the Isle of Wight coast.

The garden is on the site of the Royal National Hospital for Diseases of the Chest, a sanatorium that was established there to exploit the same mild climate. Founded by Arthur Hill Hassall and opened in 1869 as the National Cottage Hospital for Consumption and Diseases of the Chest, it offered 130 separate south-facing bedrooms for its patients. The hospital was closed in 1964, made obsolete by drug treatment of tuberculosis, and demolished in 1969.[1]

In 1970, the site was initially redeveloped as the Steephill Pleasure Gardens before Sir Harold Hillier's involvement in its more extensive development as a botanical garden. Despite the generally mild weather, plants had to be carefully selected to tolerate the shallow alkaline soil and salt winds, and the garden suffered serious damage in the unusually hard winter of 1986/7, the Great Storm of 1987 and another major storm of January 1990. The garden is still owned and managed by the Isle of Wight Council, and continues to develop with numerous new features. The current curator of the garden is Simon Goodenough.

The garden is located on the A3055 road, has a large car park, and public transport is provided by buses on Southern Vectis' route 6 and Wightbus' route 16.