Justin Dwinell (October 28, 1785 Shaftsbury, Bennington County, Vermont – September 17, 1850 Cazenovia, Madison County, New York) was an American lawyer and politician from New York.
Then he studied law in Troy with John D. Dickinson, was admitted to the bar in 1811, and commenced practice in Cazenovia.
On September 12, 1813, he married Louise Whipple, and they had nine children, among them California Assemblyman John W. Dwinelle (1816–1881).
Justin Dwinell was member of the New York State Assembly (Madison Co.) in 1820–21 and 1822.
He was buried at the Evergreen Cemetery in Cazenovia, New York.