| William Cragin | |
| Fullname: | William B. Cragin Jr.[1] |
| Birth Date: | September 21, 1876 |
| Birth Place: | Fairfield, Connecticut, US |
| Death Place: | Los Angeles, California, US |
| Usopenresult: | QF (1909, 1910) |
William B. Cragin Jr. (September 21, 1876 – September 16, 1943) was an American tennis player active in the early 20th century.
Cragin reached the quarterfinals of the U.S. National Championships in 1909 and 1910, having to qualify in the former via the preliminary round. In 1911 and 1912 he was runner-up in singles at the U.S. National Indoor Championships.