Loudon
The taxon authority Loudon may refer to:
- Ben J. Loudon (B. K. Loudon), Australian entomologist
- Harald von Loudon (1876–1959), Baltic-German ornithologist
- Jane Wells Loudon (1807–1858, J.W.Loudon), English botanist
- John Claudius Loudon (1783–1843, Loudon), Scottish botanist