Harold Delos Babcock (January 24, 1882 – April 8, 1968) was an American astronomer, and the father of Horace W. Babcock. Of English and German ancestry. He was born in Edgerton, Wisconsin before completing high school in Los Angeles and was accepted in the University of California, Berkeley in 1901. He worked at the Mount Wilson Observatory from 1907 until 1948. He specialized in solar spectroscopy and mapped the distribution of magnetic fields over the Sun's surface. With his son he revealed the existence of strong magnetic fields in certain stars. In 1953 he won the Bruce Medal.
The crater Babcock on the Moon is named after him, as is asteroid 3167 Babcock (jointly named after him and his son).