Nicholas A. Mattiello (born 1963) is an American politician and Democratic former member of the Rhode Island House of Representatives, who represented the 15th District from 2007 to 2021. He served as the Speaker of the Rhode Island House of Representatives from March 25, 2014 to 2021. In 2020, he was defeated in an upset by Republican Barbara Ann Fenton-Fung, the wife of Cranston mayor Allan Fung.