Leon Campbell (January 20, 1881 – May 10, 1951) was an American astronomer. He is noted for his observations of variable stars at the Harvard College Observatory. He served as Recorder of Observations for the AAVSO from its earliest days in 1915, and continued until his retirement in the 1940s. (The title was later changed to Director of the AAVSO.) He also published a number of papers and a pair of books on the topic of variable stars.