| William Miller Collier | |
| Ambassador From: | United States |
| Country: | Spain |
| Term Start: | March 8, 1905 |
| Term End: | June 9, 1909 |
| Predecessor: | Arthur S. Hardy |
| Successor: | Henry Clay Ide |
| Ambassador From2: | United States |
| Country2: | Chile |
| Term Start2: | 1921 |
| Term End2: | 1928 |
| Successor2: | William S. Culbertson |
| Term Start3: | 1918 |
| Term End3: | 1921 |
| Successor3: | William Mather Lewis |
| Birth Date: | 11 November 1867 |
| Birth Place: | Lodi, New York |
| Death Place: | West Caldwell, New Jersey |
| Nationality: | American |
William Miller Collier (November 11, 1867 – April 15, 1956) was United States Ambassador to Spain from 1905 to 1909, the president of George Washington University from 1918 to 1921, and United States Ambassador to Chile from 1921 to 1928.
He was born November 11, 1867, in Lodi, New York. He graduated from Hamilton College with a B.A. in 1889 and then a M.A. in 1892. He was a member of the Chi Psi fraternity at Hamilton College.
After receiving his law degree, he was admitted to the New York State Bar Association in 1892 and he then established a law firm in Auburn, New York where he practiced until 1903. From 1903 to 1904 he worked in the office of the United States Attorney General concentrating on antitrust issues. In 1904 he was nominated to be an attorney for the Department of Commerce and Labor.[1]
He was United States Ambassador to Spain from 1905 to 1909. He gave a series of lectures on international law at New York University Law School from 1912 to 1918.[2] He then served as president of George Washington University from 1918 to 1921. He became the United States Ambassador to Chile from 1921 to 1928.[3]
He died on April 15, 1956, in West Caldwell, New Jersey while visiting his niece, Mrs. James Franklin.[4]