Robert Morrison, D.D. (March 15, 1822 – July 27, 1902) was an American Presbyterian minister, teacher and editor who was the principal founder of Phi Delta Theta international college fraternity.
Morrison grew up in Ohio and entered Ohio University in 1839 as a scholarship student. He attended Ohio University for two years, returning home to help on the family farm and to teach school. He entered Miami University in 1846 and conceived the idea for the Phi Delta Theta which he founded with five other students on December 26, 1848. He was awarded an honorary M.A. degree and a D.D. degree from Miami University.
His career as a minister, editor of religious publications and teacher took him to Tennessee, Kentucky, Ohio and Missouri. He died at his home near Fulton, Missouri in 1902, second to last of the six founders of Phi Delta Theta to survive.