The genus Flabellina was established by John Edward Gray in 1833 with the type species Flabellina affinis and characterised by the cerata being arranged on peduncles and the rhinophores being annulate. Many species were added by subsequent authors. In 1981 the genus Coryphella was merged under the older name Flabellina as despite a large range of morphological characters in the 64 species of Flabellinidae and Coryphellidae known at that time, no clear distinction could be found to separate the species into the two genera. In 2017 an integrative study of the 71 species then considered being included in Flabellina redistributed the species into seven families and 26 genera.