Harold Jacoby (4 March 1865 – 20 July 1932) was an American astronomer, born in New York City.

Columbia's Rutherfurd Observatory was started during his tenure, with a twelve-inch Clarke refractor telescope and a transit instrument emplaced atop Pupin Hall.

Jacoby made many observations of celestial events such as lunar and solar eclipses.

He was well known in Europe and America, and was a member of a large number of scientific groups.

He published Practical Talks by an Astronomer (1891, 1902), Astronomy: A Popular Handbook (1913)[3][4] and Navigation (1917).