John Kirk Townsend (October 10, 1809 – February 6, 1851) was an American naturalist, ornithologist and collector.

Townsend was born in Philadelphia and trained as a physician and pharmacist. He developed an interest in natural history in general and bird collecting in particular. In 1833 he was invited by the botanist Thomas Nuttall to join him on Nathaniel Wyeth 's second expedition across the Rocky Mountains to the Pacific Ocean. Townsend collected a number of birds new to science, including the Mountain Plover, Chestnut-collared Longspur, Black-throated Gray Warbler, Townsend's Warbler and Sage Thrasher.

On his return Townsend wrote The Narrative of a Journey across the Rocky Mountains to the Columbia River and a Visit to the Sandwich Islands (1839).

A number of mammals are named for Townsend, including Townsend's Ground Squirrel , Townsend's Chipmunk , Townsend's Pocket Gopher , Townsend's Mole, Townsend's Vole and the Whitetail Jackrabbit Lepus townsendi.