Notodiaptomus is a genus of copepods in the family Diaptomidae.

It is the most widely distributed, most abundant and most species-rich genus of freshwater calanoid copepods in the Neotropics.

[1] The genus was erected in 1936 by Friedrich Kiefer for eleven species formerly placed in a wider Diaptomus.

Notodiaptomus deitersi was chosen to be the type species by Raúl Adolfo Ringuelet in 1958.

[2] Its members include the Venezuelan endemic Notodiaptomus maracaibensis and the Brazilian endemic Notodiaptomus dubius, both of which are listed as vulnerable species on the IUCN Red List.