John Kirk Townsend (August 10, 1809 – February 6, 1851) was an American naturalist, ornithologist and collector.
Townsend was a Quaker born in Philadelphia, the son of Charles Townsend and Priscilla Kirk. He attended Westtown School in West Chester, Pennsylvania and was 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 Jarvis Wyeth's second expedition across the Rocky Mountains to the Pacific Ocean. Townsend collected a number of animals new to science. These included birds such as the mountain plover, Vaux's swift, chestnut-collared longspur, black-throated grey warbler, Townsend's warbler and sage thrasher, and a number of mammals such as the Douglas squirrel; several of these were described by Bachman (1839) from samples collected by Townsend.