After a long history of controversial classifications, in 2021 it was recognized as a phylogenetically distinct lineage from the rest of ochrophyte classes.

[7] A thesis from 1999 proposed Olisthodiscophyceae as a separate class for the first time, but it was never published in a peer-reviewed journal.

[2] With the use of molecular phylogenetic analyses, Olisthodiscus appeared as a branch outside Raphidophyceae or any other described ochrophyte class.

It was proposed that Sulcochrysis belonged to this class along with Olisthodiscus, but due to lack of DNA sequences from this organism it could not be confirmed.

[2] Bacillariophyceae Pelagophyceae Dictyochophyceae Raphidophyceae Xanthophyceae Phaeophyceae Olisthodiscophyceae Pinguiophyceae Synchromophyceae Chrysophyceae Eustigmatophyceae Apart from the type species described in 1937, Olisthodiscus luteus, two other species were added in the 20th century: O. carterae and O. magnus, which were later recognized as conspecific with Heterosigma akashiwo and Chattonella marina respectively.