Otto von Wettstein, name also given as Otto Wettstein-Westersheimb, (7 August 1892, in Vienna – 10 July 1967) was an Austrian zoologist. He was the son of botanist Richard Wettstein and the brother of botanist Fritz von Wettstein. He is best remembered for his work in the field of herpetology; of his 205 published scientific papers, 60 of these involved herpetological topics. After World War II, he worked as a forestry manager at the Federal Research Institute of Forestry in Mariabrunn. A subspecies of viper, Vipera ursinii wettsteini (Knöpfler & Sochurek, 1955) is named after him.