Johan Georg Ludvig Manthey (3 June 1769 – 18 January 1842) was a Danish pharmacist.

He was also employed as a teacher at the pharmacy of Frederiks Hospital in spite of the fact that he had not apprenticed as a pharmacist.

[1] In 1791, Manthey succeeded Christopher Günther, his father-in-law, as pharmacist and owner of The Lion Pharmacy on Amagertorv in Copenhagen.

This resulted in protests from the Medical Board (Det medicinske Kollegium) due to his lack of formal training as a pharmacist.

He wrote a substantial number of scientific articles and contributed to Pharmacopoea Danica (1805).