Chavalit Vidthayanon (Thai: ชวลิต วิทยานนท์; born 1959 in Bangkok) is a Thai ichthyologist and senior researcher of biodiversity of WWF Thailand.
Vidthayanon received a Ph.D. in fishery biology from the Tokyo Fisheries University (present-day Tokyo University of Marine Science and Technology), Japan.
He has been working on aquatic biodiversity studies in Southeast Asia since 1983.
He has worked with leading ichthyologists both Thais and foreigners such as Kittipong Jaruthanin, T. R. Roberts, H. H. Ng and Maurice Kottelat etc.
He has studied and taxonomy many of the newly discovered freshwater species in the world (many were found in Mekong Basin) such as Amblypharyngodon chulabhornae, Himantura kittipongi, Pangasius conchophilus, P. myanmar, Pao palustris, Pseudeutropius indigens, Schistura pridii etc.