David Douglas (25 June 1799 – 12 July 1834) was a Scottish botanist. The son of a stonemason, he was born in the village of Scone north-east of Perth. He attended Kinnoull School and upon leaving he found work as an apprentice gardener in the estate of the 3rd Earl of Mansfield at Scone Palace. He spent seven years at this position before leaving to attend college in Perth to learn more of the scientific and mathematical aspects of plant culture. After a further spell of working in Fife (during which time he had access to a library of botanical and zoological books) he moved to the Botanical Gardens of Glasgow and attended botany lectures at the University of Glasgow. The Professor of Botany was greatly impressed with him and took him on an expedition to the Highlands before recommending him to the Royal Horticultural Society of London.

Coast Douglas-fir cone, from a tree grown from seed collected by David Douglas in 1826On behalf of Sir William Hooker of the Royal Botanic Institution of Glasgow, the resourceful and often intrepid Douglas undertook a plant-hunting expedition in the Pacific Northwest in 1824 that ranks among the great botanical explorations of a heroic generation. The Douglas-fir, which he introduced into cultivation in 1827, is named after him. However, the tree's scientific name, Pseudotsuga menziesii, honors a rival botanist, Archibald Menzies. Other notable introductions include Sitka Spruce, Sugar Pine, Western White Pine, Ponderosa Pine, Lodgepole Pine, Monterey Pine, Grand Fir, Noble Fir and several other conifers that transformed the British landscape and timber industry, as well as numerous garden shrubs and herbs such as the Flowering currant, Salal, Lupin, Penstemon and California poppy. His success was well beyond expectations; in one of his letters to Hooker, he wrote "you will begin to think I manufacture pines at my pleasure". Altogether he introduced about 240 species of plants to Britain. He died under mysterious circumstances in Hawai'i at the age of 35 when he apparently fell into a pit trap and was possibly crushed by a bull that fell into the same trap. He was last seen at the hut of Englishman Edward "Ned" Gurney, a bullock hunter and escaped convict. Gurney was also suspected in Douglas's death, as Douglas may have been carrying gold in a money purse. Douglas was buried in an unmarked common grave near Mission House in Honolulu. Later, in 1856, a marker was erected on an outside wall at Kawaiaha'o Church. A monument was built at the spot where Douglas died. It is located in Kaluakauka ("DR's Pit") off Mana Road on the Island of Hawai?i.

There is a memorial to David Douglas in his birthplace of Scone.