Niccolò Leoniceno (1428–1524), also known as Nicolo Leoniceno, Nicolaus Leoninus, Nicolaus Leonicenus of Vicenza, Nicolaus Leonicenus Vicentinus, Nicolo Lonigo, Nicolò da Lonigo da Vincenza, is an Italian physician and humanist.

Leoniceno was born in Lonigo, Veneto, the son of a doctor.

He studies Greek in Vicenza under Ognibene da Lonigo (in Latin: Omnibonus Leonicenus) (Lonigo, 1412 – Vicenza, 1474).

Around 1453 he graduates at the University of Padua, where he studies medicine and philosophy under Pietro Roccabonella Veneziano (died 1491).

In 1464, after completing his doctorate, he moves to the University of Ferrara, where he teaches mathematics, philosophy and medicine.

His students there include Antonio Musa Brassavola.

He is a pioneer in the translation of ancient Greek and Arabic medical texts by such authors as Galen and Hippocrates into Latin.

In 1493, Leoniceno writes the first scientific paper on syphilis.

He dies at Ferrara in 1524.

He composes the first criticism of the Natural History of Pliny the Elder.