William Wallace Campbell (11 April 1862 – 14 June 1938) was an American astronomer, and director of Lick Observatory from 1900 to 1930. He specialized in spectroscopy.
He was born on a farm in Hancock county, Ohio, the son of Robert Wilson and Harriet Welsh Campbell. After a few years of local schooling he entered in 1882 the University of Michigan to study civil engineering, graduating Bachelor of Science in 1886. Whilst at university he developed his interest in astronomy when he read Simon Newcomb's Popular Astronomy.
