John Merle Coulter, Ph. D. (November 20, 1851 – December 23, 1928) was an American botanist and educator, brother of Stanley Coulter, born at Ningpo, China. He received his education at Hanover College in Indiana. He served in the Rocky Mountains for two years (1872–73) as botanist to the United States Geological Survey. He became professor of natural science at Hanover College, professor of biology at Wabash College (1879), president of Indiana University from 1891 to 1893, and from 1893 to 1896 he presided over Lake Forest University. In 1896 he became head of the department of botany at the University of Chicago. In 1875 he founded Botanical Gazette and thereafter continued to be its editor.
In 1909, Coulter and his wife Grace, along with their children Grace and Merle, survived the sinking of the White Star liner Republic in which six were killed.
In 1925, Coulter moved to Yonkers, New York to help organize the new Boyce Thompson Institute for Plant Research, of which he was dean and chief advisor. He died in Yonkers in 1928.