The University of Rennes, founded in 1840, houses nearly 1 million geological specimens, including those inherited from the municipal museum, which closed in 1944. Several micropaleontological collections of significant interest to the scientific community are deposited in the university’s geological museum. Most of them concern Paleozoic ostracods (particularly the Nion, Vannier and Rouault collections) and chitinozoans (Paris coll.) from the Armorican massif and peri-Gondwanan terranes, as well as Cenozoic pollen and spores from western France (Ollivier-Pierre collection). More recently, studies on Jurassic and Cretaceous charophytes and palynology have been developed within the Geosciences Rennes laboratory, and the resulting material has been incorporated into the museum collections (Polette and Benoît collections). Here, we provide brief summaries of these collections with lists of type and figured specimens curated at the University of Rennes.