| Pliny L. Allen | |
| Office: | President pro tempore of the Washington Senate |
| Term Start: | January 13, 1913 |
| Term End: | January 11, 1915 |
| Predecessor: | W. H. Paulhamus |
| Successor: | Edward L. French |
| Office1: | Member of the Washington House of Representatives for the 43rd district |
| Term1: | 1919 - 1933 |
| Office2: | Member of the Washington State Senate for the 33rd district |
| Term2: | 1907 - 1915 |
| Birth Date: | 27 November 1873 |
| Birth Place: | Wisconsin, United States |
| Death Place: | Washington, United States |
| Party: | Republican |
Pliny Lee Allen (November 27, 1873 - August 6, 1967) was an American politician in the state of Washington. He served in the Washington House of Representatives and Washington State Senate.[1] From 1913 to 1915, he was president pro tempore of the Senate.