| Oliver Deveta Hamlin Jr. | |
| Office: | Senior Judge of the United States Court of Appeals for the Ninth Circuit |
| Term Start: | September 5, 1963 |
| Term End: | December 28, 1973 |
| Office1: | Judge of the United States Court of Appeals for the Ninth Circuit |
| Term Start1: | March 26, 1958 |
| Term End1: | September 5, 1963 |
| Appointer1: | Dwight D. Eisenhower |
| Predecessor1: | William Denman |
| Successor1: | Walter Raleigh Ely Jr. |
| Office2: | Judge of the United States District Court for the Northern District of California |
| Term Start2: | August 3, 1953 |
| Term End2: | April 15, 1958 |
| Appointer2: | Dwight D. Eisenhower |
| Predecessor2: | Monroe Mark Friedman |
| Successor2: | Lloyd Hudson Burke |
| Birth Name: | Oliver Deveta Hamlin Jr. |
| Birth Date: | 30 November 1892 |
| Birth Place: | Oakland, California |
| Education: | University of California, Berkeley (BL) |
Oliver Deveta Hamlin Jr. (November 30, 1892 – December 28, 1973) was a United States circuit judge of the United States Court of Appeals for the Ninth Circuit and previously was a United States district judge of the United States District Court for the Northern District of California.
Born in Oakland, California, Hamlin received a Bachelor of Laws from the University of California, Berkeley in 1914. He was a deputy district attorney of Alameda County, California from 1915 to 1920, and was in private practice in Oakland from 1920 to 1947. He was a Judge of the Alameda County Superior Court from 1947 to 1953.
Hamlin was nominated by President Dwight D. Eisenhower on July 23, 1953, to a seat on the United States District Court for the Northern District of California vacated by Judge Monroe Mark Friedman. He was confirmed by the United States Senate on August 1, 1953, and received his commission on August 3, 1953. His service terminated on April 15, 1958, due to his elevation to the Ninth Circuit.
Hamlin was nominated by President Eisenhower on March 6, 1958, to a seat on the United States Court of Appeals for the Ninth Circuit vacated by Judge William Denman. He was confirmed by the Senate on March 25, 1958, and received commission the next day. He assumed senior status on September 5, 1963. His service terminated on December 28, 1973, due to his death.