Murine norovirus, also known as MNV, is a species of norovirus affecting rodents, specifically, mice. MNV is the most common gastrointestinal pathogen of research mice and can alter research outcomes in biomedical mouse models of inflammatory bowel disease (IBD). Murine noroviruses share pathogenic properties with human noroviruses. Specifically, they are infectious orally, they spread between mice, and at least one strain, MNV-1, causes mild diarrhea in their hosts.

MNV is transmitted via the fecal-oral route with tropism for dendritic cells and macrophages. As a result, the virus spreads rapidly through dense populations, such as in research facilities, where mice are kept in close quarters.