Nicolò Grassi, also known as Nicola Grassi, was an Italian painter, active in a late-Baroque or Rococo style.

He was born in Formeaso in the Friuli and died in Venice.

After studying as an apprentice with Antonio Carneo he moved to Venice in 1697 after his death. He worked with the Genovese artist Nicolo Cassana until 1709.

In 1710 he was recognized for his work The Virgin with Child and two saints. Between 1722 and 1725 he went to Bavaria and then to Dalmatia.