Neoplagiaulacidae is a family of mammal within the extinct order Multituberculata. Fossil remains are known from the Upper Cretaceous through the Eocene. Representatives have been found in North America, Europe and Asia.Neoplagiaulacinae (Ameghino 1890) has been seen as a sub-family within Ptilodontidae (Cope, 1887). More recent thinking has it as a family. Synonyms are Ectypodidae (Sloan & Van Valen 1965) and Ectypodontidae (Sloan & Van Valen 1965).