Waldo is the surname of:
People Charles Waldo (1819–1909), American politician in Wisconsin Clarence Abiathar Waldo (1852–1926), American mathematician, author, and educator Daniel Waldo (1762–1864), veteran of the American Revolutionary War, missionary and U.S. House clergyman Daniel Waldo (Oregon pioneer) (1800–1880), American legislator in the Provisional Government of Oregon Dr. Dwight B. Waldo (1864–1939), first president of Western Michigan University Dwight Waldo (1913–2000), American political scientist Edward Hamilton Waldo, birth name of American science fiction author Theodore Sturgeon (1918–1985) Elisabeth Waldo (1918–2026), American violinist, composer and ethnomusicologist George E. Waldo (1851–1842), American politician Janet Waldo (1920–2016), American actress and voice artist Jim Waldo, computer scientist and software architect John B. Waldo (1844–1907), jurist and conservationist in Oregon, United States Katita Waldo (born 1968), Spanish ballet dancer and ballet master Octavia Waldo (born 1929), American writer Peter Waldo (1140–1218), founder of a Christian sect called the Waldensians Rhinelander Waldo (1877–1927), US Army captain, Fire and later Police Commissioner of New York City Samuel Waldo (1696–1759), Massachusetts land speculator, soldier and political figure Samuel Lovett Waldo (1783–1861), American painter William Waldo (California politician) (1812–1881) William Waldo (Oregon politician) (1832–1911)
Fictional characters Mr Waldo, a main character in Under Milk Wood, a Dylan Thomas play