ABSTRACT The Trebouxiophyceae is a widespread and species-rich green algal class encompassing mostly coccoid algae with a simple spherical, ovoid or ellipsoidal outline. However, some poorly sampled lineages have evolved more elaborate shapes or even complex thalli, adding to the morphological diversity of the class. By investigating new and previously established strains, this study expands the range of morphologies exhibited by the class members by uncovering a clade of croissant-like trebouxiophytes. Phylogenetic analyses inferred from nuclear 18S rDNA and chloroplast rbcL sequences confirmed the monophyly of the ‘microcroissant’ clade, which we propose to be classified as a new family, Ragelichloridaceae. This family includes two novel genera, Ragelichloris and Navichloris, and the previously described Thorsmoerkia. The position of Ragelichloridaceae within Trebouxiophyceae stayed unresolved but chloroplast phylogenomics showed that the family belongs to the broader incertae sedis group that also includes Xylochloris and Leptosira. In addition, our study showed that the similar morphotype-bearing genus Chlorolobion, previously classified within Chlorophyceae, is a genuine trebouxiophyte, potentially related to Ragelichloridaceae.