William Huggins (February 7 1824 – May 12 1910) was a British astronomer.

He built a private observatory and did extensive observations of the spectral emission lines and absorption lines of various celestial objects. He was the first to distinguish between nebulas and galaxies by showing that some (like the Orion Nebula) had pure emission spectra characteristic of gas, while others like the Andromeda Galaxy had spectra characteristic of stars.

He won the Gold Medal of the Royal Astronomical Society in 1867 jointly with William Allen Miller, and then again, alone, in 1885. He also won the Copley Medal in 1898 and the Bruce Medal in 1904.

The Huggins crater on the Moon and a crater on Mars are named after him, as is the asteroid 2635 Huggins .