Lensia is a genus of hydrozoans belonging to the order Siphonoporae and the family Diphyidae. This genus is colonial and consists of many different types of highly specialized zooids. The genus Lensia was first established in 1932 by Dr. Arthur Knyvett Totton, who would also describe and add another 11 species during his career. As of March 2023, the genus consists of only 26 described and accepted species and an additional seven uncertain species, according to the World Register of Marine Species.