Armin Otto Leuschner (January 16, 1868 – April 22, 1953) was an American astronomer and educator.

Leuschner then became the first graduate student at Lick Observatory, but due to conflicts with his advisor, Lick director Edward S. Holden, he left Lick before finishing his Ph.D. Leuschner subsequently returned to Germany and attended the University of Berlin, where in 1897 he earned his doctorate with a highly praised thesis on the orbits of comets.

Leuschner's own research continued to focus on the orbits of asteroids and comets; this subject required tremendous amounts of detailed computation, which made the work well-suited to be shared with a long series of students, many of whom went on to successful astronomical careers of their own.

In 1913, Leuschner became dean of the entire Graduate School at Berkeley, and later was appointed head of all World War I related training at the university.

He was a founding member of the Astronomical Society of the Pacific, served a term as the president of the American Association of University Professors, and chaired the International Astronomical Union's committee on comets and minor planets for two decades.