Megachile campanulae was originally described in 1903 under the name Oligotropus campanulae by Charles Robertson, an American entomologist from Carlinville, Illinois. Megachile translates from Greek mega (μεγας) 'large' + cheil- (χειλ) 'lip'. In Latin, campanulae translates as "small bell". M. campanulae has been documented to frequent flowers in the genus Campanula, several species of which are commonly referred to as bellflowers. Subspecies include M. campanulae campanulae and M. campanulae wilmingtoni. The genus Megachile is a cosmopolitan group of solitary bees, often called leafcutter bees and resin bees. It is one of the largest genera of bees, with 1520 species in 56 subgenera worldwide.
