| Walter Macarthur | |
| Office: | United States Shipping Commissioner |
| Appointer: | William C. Redfield |
| Term Start: | 1913 |
| Term End: | 1932 |
| Birth Date: | 9 March 1862 |
| Birth Place: | Glasgow, Scotland |
| Death Place: | San Francisco, California, U.S. |
| Resting Place: | Cypress Lawn Memorial Park |
| Nationality: | Scottish |
| Party: | Democratic Union Labor |
| Allegiance: |  United Kingdom United States |
| Branch: | British Merchant Navy U.S. Merchant Marine |
Walter Macarthur (March 9, 1862 - December 8, 1944) was a Scottish-American labor leader and writer who served nearly twenty years as a United States Shipping Commissioner.[1] He was one of the founders of the Sailors' Union of the Pacific, and was the longtime editor of its official organ, the Coast Seamen's Journal.[2] He was involved with the San Francisco Union Labor Party before disavowing it over its corruption,[3] and was a co-founder of the Asiatic Exclusion League.[4] In 1910 he ran for Congress against Julius Kahn.