Robert Alexander Campbell (September 2, 1832 – April 2, 1926) was a nineteenth-century politician, lawyer and businessman from Missouri.

After teaching school for one term he went to California with his father and worked in ranching and mining for two years.

He returned to Missouri in 1854, and eventually studied law and was admitted to the bar in 1860.

He fought in the Civil War and then returned to law practice until 1869, when he moved into railroads through 1877.

He served in the Missouri general assembly starting in 1869, and was eventually named speaker pro tem.