show Abstracthide AbstractMicroRNAs (miRNAs) are important regulators of gene expression in both plants and animals. They are thought to have evolved convergently in these lineages and hypothesized to have played a role in the evolution of multicellularity. In line with this hypothesis, miRNAs have so far only been described in a handful of unicellular eukaryotes. In this study we investigate the presence and evolution of miRNAs in Amoebozoa, focusing on species belonging to dictyostelid, Physarum, and Acanthamoeba taxonomic groups, representing true unicellular species as well as species where cells go through aggregative multicellularity.