Mariano de la Paz Graells y de la Agüera (1809–1898) was a Spanish entomologist notable for pioneering work on the insects of corpses.
Graells was born in Tricio, in the Province of Logroño. He died in Madrid where he had been professor of zoology.
The moth genus Graellsia and the Graells's tamarin are named after him.He also identified the Iberian badger subspecies Meles meles marianensis.