MSI1-like WD40 repeat proteins are subunits of many protein complexes controlling chromatin dynamics. These proteins do not have any catalytic activity, but several recent studies using loss-of-function mutants established specific functions during development. Here, we review the current knowledge of MSI1-like proteins, including their phylogenetic history, expression patterns, biochemical interactions and mutant phenotypes. MSI1-like proteins, which are often targets or partners of tumor-suppressor proteins, are required during cell proliferation and differentiation in flies, nematodes and plants. We discuss the possibility that MSI1-like proteins could function to maintain epigenetic memory during development by targeting silencing complexes to chromatin during nucleosome assembly.