New dinoflagellate cyst taxa have been recovered from Pliocene deposits in the Antwerp area of Belgium, where a detailed analysis of the Kattendijk and Lillo formations has yielded a diverse dinoflagellate record for the southern margin of the North Sea Basin. Four new species and two new genera of dinoflagellate cysts are recognized: the gonyaulacaceans Spiniferites coniconcavus n. sp. and Pyxidinopsis braboi n. sp., the goniodomacean Desotodinium wrennii n. gen. and sp., and the protoperidiniacean Scaldecysta doelensis n. gen. and sp. The protoperidiniacean genus Barssidinium Lentin, Fensome, and Williams, 1994 has been emended from new observations on the tabulation of Barssidinium pliocenicum (Head, 1993) Head, 1994a emend. The excellent preservation of the Belgian material accounts for these new observations. Barssidinium wrennii Lentin, Fensome, and Williams, 1994 is considered a taxonomic junior synonym of Barssidinium pliocenicum (Head, 1993) Head, 1994a, which thus becomes the correct name for the type of the genus. The new marine incertae sedis palynomorph Waaslandia geminifera n. gen. and sp. is also proposed.