Isaac Volney Baker Jr. (August 15, 1843 Comstock's Landing, Fort Ann, Washington County, New York – December 14, 1912 Hudson Falls, Washington Co., NY) was an American politician from New York.
He was the son of Isaac V. Baker (1813–1894) and Laura Daley (Comstock) Baker (1819–1877). He attended North Granville Academy, and Brooklyn Polytechnic and Collegiate Institute. Then he engaged in mercantile and agricultural pursuits, especially in breeding Merino sheep.
On September 14, 1865, he married Laura Demis Clark (1844–1930), and they had several children.
He was a member of the New York State Assembly (Washington Co., 2nd D.) in 1869, 1870 and 1871; of the New York State Senate (12th D.) in 1872 and 1873; again of the State Assembly in 1877; and again of the State Senate (16th D.) in 1880 and 1881.
He was New York Superintendent of State Prisons from 1882 to 1887. He was New York State Railroad Commissioner from 1887 to 1892.
He died of pneumonia on December 14, 1912 in Hudson Falls, New York at age 69.
He was buried at the Baker Cemetery in Fort Ann.