William Albert Hiltner (27 August 1914 – 30 September 1991) was an American astronomer, noted for his work leading up to the discovery of interstellar polarization.

[1][2] He was an early practitioner of precision stellar photometry, and a pioneering observer of the optical counterparts of celestial x-ray sources.

Director of Yerkes Observatory for many years, while there he designed and built a rotatable telescope for polarization studies and developed photometric instrumentation.

Gaining an interest in astronomy at an early age, he graduated from high school in a class of 17, and entered the University of Toledo the following year.

Stephen K. Hiltner is a jazz musician and composer, and founded the nonprofit Ellerbe Creek Watershed Association and Friends of Herrontown Woods.