M. polymorpha may refer to:
Macrozamia polymorpha, a plant endemic to New South Wales, Australia Marchantia polymorpha, a large liverwort Martinia polymorpha, a perennial herb Medicago polymorpha, a plant native to the Mediterranean Basin Melanoides polymorpha, a freshwater snail Metrosideros polymorpha, an evergreen tree Mima polymorpha, a gram-negative bacterium Mitra polymorpha, a sea snail Mitrasacme polymorpha, a perennial herb Moquinia polymorpha, a sunflower native to Brazil, Bolivia, and Paraguay Moraxella polymorpha, a gram-negative bacterium Munidopsis polymorpha, a squat lobster Mycosphaerella polymorpha, a plant pathogen Mylabris polymorpha, a blister beetle