Dinophysis is a dinoflagellate genus (Dinophysiales, Dinophyceae) with more than 200 recognised species found in coastal and oceanic waters throughout the World . Cell densities are usually neglestible, but favourable conditions can result in massive blooms also known as red tides. Attention to Dinophysis greatly increased as several species of the genus was linked to the toxin responsible for the toxic syndrome diarrhetic shellfish poisoning (DSP), a gastrointestinal illness causing huge economical losses for the mussel industry, especially around Europe and Japan.

The first culture of Dinophysis was established by feeding the photosinthetic Dinophysis acuminata with the ciliate Myreonecta rubra.

Dinophysis includes heterotrophic and photosynthetic species. Only photosynthetic species (mixotrophic) have been linked to DSP.

Common species within the genus include Dinophysis acuminata, D. acuta, D. norvegica, D. caudata and D. tripos