Mollisonia is a genus of epifaunal detritivorous arthropod. Species are known from the Cambrian Burgess Shale, Langston Formation and Wheeler Shale of North America, as well as the Chengjiang Biota of China. Twenty-one specimens of Mollisonia are known from the Greater Phyllopod bed, where they comprise less than 0.1% of the community. Remains attributed to the genus are also known from the Ordovician Fezouata Formation of Morocco and Greenland. An observation published in 2019 suggests this genus is a basal chelicerate, closer to crown group Chelicerata than members of . It is suggested to be closely related to , and Thelxiope, together forming the clade Mollisoniida.