Reuben D. Smart (December 24, 1832 – June 6, 1890) was an American lumberman and politician.
Born in Saint Patrick Parish, Charlotte County, New Brunswick, Canada, Smart emigrated to the United States in 1855 and settled in Manitowoc, Wisconsin.
In 1872, Smart was elected sheriff of Manitowoc County, Wisconsin and was a Republican.
He also served as deputy collector of internal revenue.
This article about a Republican Party member of the Wisconsin State Assembly born in the 1830s is a stub.