Viridans may refer to:
Viridans streptococci, large group of bacteria species Achatinella viridans, species of mollusc Aerococcus viridans, species of bacteria Apotoforma viridans, species of moth Blennidus viridans, species of ground beetle Ericydeus viridans, species of true weevil Eucalyptus socialis subsp. viridans, species of plant Gymnopilus viridans, species of mushroom Pasimachus viridans, species of ground beetle Peucetia viridans, species of spider Sorotacta viridans, species of moth Synema viridans, species of crab spider Thalassomonas viridans, species of bacteria Trichiotinus viridans, species of beetle