Gonyaulax is a genus of dinoflagellates with the type species Gonyaulax spinifera (Claparède et Lachmann) Diesing.

[4] The plate formula in the genus Gonyaulax Diesing was redefined as Po, 3', 2a, 6", 6c, 4-8s, 5'", 1p, 1"".

[5] It previously included several species, which are now considered to belong to a separate genus, e.g.:[5] Gonyaulax dinoflagellates can produce resting cysts that belong to the cyst-defined genus Spiniferites and other genera [6] Although some Gonyaulax species can produce yessotoxins, which can accumulate in shellfish, no harmful effects to humans have been clearly demonstrated; however abalone mortalities have been related to blooms of Gonyaulax membranaceae.

[7] A Red tide is a discoloration of the sea water by pigmented cells like Gonyaulax spp., some of which may produce toxins.

Gonyaulax spinifera has been connected to the production of yessotoxins (YTXs), a group of structurally related polyether toxins, which can accumulate in shellfish.