Cretaceous bryozoans from western North America are very poorly known. This paper describes twelve species of cheilostomes from the Upper Cretaceous of southern California and Baja California. The only previously described bryozoan, Ceriocava eastoni Woollacott, 1966, from the Holz Member (?Turonian–Campanian), Ladd Formation of the Santa Ana Mountains, is transferred from Cyclostomata to Cheilostomata, made the type species of the new genus Zimmerella and placed in the family Chiplonarinidae. The following new Campanian– Maastrichtian species are described from the Rosario, Point Loma, and Cabrillo formations of San Diego County, California and Le Misión, Baja California: Wilbertopora sannerae sp. nov., Onychocella schopforum sp. nov., Trichinopolia californica sp. nov., and T. lata sp. nov.