John Jeffrey (14 November 1826 – 1854) was a Scottish botanist and plant-hunter active in the United States.
Jeffrey was born in Forneth, Parish of Clunie, west of Blairgowrie and Rattray in east Perthshire.
Jeffrey arrived at Hudson Bay in August 1850 and travelled more than 1,200 miles (1,900 km) overland to reach the Columbia River.
He then spent the next four years exploring Washington, Oregon, and California, sending his specimens back to Scotland.
At the time, Jeffrey was criticised for poor results but his discoveries, particularly of conifers, were significant.