Botanical Garden St. Gallen, Botanical garden in St. Gallen, Switzerland.

Botanical Garden St. Gallen displays over 8000 plant species from different parts of the world. The grounds include tropical houses, alpine gardens, and various zones designed for different climates.

The garden was founded in 1878 as part of the city's development and was originally located in the City Park. It moved several times over the decades before reaching its current location in 1945.

The garden's school departments cover biology, genetics and systematics; the genetics section centres on the Mendel Garden, named after Gregor Mendel, with mutations of trees and shrubs. The systematics beds were reworked and relabelled in 2013/2014 to follow new findings on plant relationships, showing about 500 species from 100 families.

The open-air grounds are freely accessible during the day; the greenhouses are also free during opening hours. The site lies on Stephanshornstrasse 4 in Neudorf, in the Stephanshorn area where the municipal nursery stood for decades. The open-air area was substantially refurbished in 2011, and its 20 departments are linked by walking paths; benches and a pergola give places to sit.

The Orangery, built in 1914 for the municipal nursery, survives with a red-tiled roof and a roof lantern; its laminated wooden beams follow the Otto Hetzer principle. Potted plants overwinter there at about 5 °C between October and May.