Octavius Valentine Catto (February 22, 1839 – October 10, 1871) was an American educator, intellectual, and civil rights activist. He became principal of male students at the Institute for Colored Youth, where he had also been educated. Born free in Charleston, South Carolina, in a prominent mixed-race family, he moved north as a boy with his family. After completing his education, he went into teaching, and becoming active in civil rights. He also became known as a top cricket and baseball player in 19th-century Philadelphia, Pennsylvania. A Republican, he was shot and killed in election-day violence in Philadelphia, where ethnic Irish of the Democratic Party, which was anti-Reconstruction and had opposed black suffrage, attacked black men to prevent their voting for Republican candidates.