Halvaria is a taxonomic grouping of protists that includes Alveolata and Stramenopiles (Heterokonta).

[2] Analyses in 2007 and 2008 revealed that the Stramenopiles and the Alveolata are related, and form a reduced clade of what were seen to be a paraphyletic group, the chromalveolates.

The two clades together with the Rhizaria (originally one of the six major eukaryote groups) form a clade dubbed the SAR supergroup.

[3][4][5] A phylogenomic analysis from 2016 cast doubt on Halvaria, suggesting that Alveolata is the sister group to Rhizaria (making the R + A clade) through new rhizarian sequence data, and that support for Halvaria might be an artifact of low taxon sampling as well as long branch attraction.

[6] However, later analyses from 2021 support Halvaria as a solid clade.