Robert Almer Harper (January 21, 1862 – May 12, 1946) was an American botanist. The younger brother of Edward Thompson Harper, Robert was born in Le Claire, Iowa to Congressional Minister Almer Harper and Eunice Thompson. The family moved to Port Byron, Illinois in 1863, where Robert attended local schools. He matriculated to Oberlin College, his father's alma mater, where he graduated with a A. B. in 1886. During the Fall of 1886 he performed graduate studies at Johns Hopkins University, then he was professor of Greek and Latin at Gates College in Neligh, Nebraska during 1886–88.