C. maxima may refer to:
Canna maxima, a perennial plant Cattleya maxima, a plant with a yellow stripe on its flower lip Cecropia maxima, a plant endemic to Ecuador Chrysoglossa maxima, a Central American moth Citrus maxima, a plant native to Asia Collocalia maxima, a cave-nesting swift Coracina maxima, a bird endemic to Australia Corylus maxima, an Old World hazel Crocomela maxima, a Bolivian moth Cucurbita maxima, a squash native to South America