Waldo is a masculine given name. It derives from the Anglo-Saxon name Waltheof. It may refer to:

People

• Waldo of Reichenau (740–814), Carolingian abbot and bishop
• Waldo Colburn (1824–1885), American politician
• Ralph Waldo Emerson (1803–1882) American writer and philosopher
• Waldo A. Evans (1869–1936), American naval captain and military governor
• Waldo Frank (1889–1967), American novelist, historian, and critic
• Waldo Grant (1946–2023), American serial killer
• Waldo E. Harder (1918–1976), president of Grace University
• M. Waldo Hatler (1894–1967), American soldier and Medal of Honor recipient
• Waldo Hutchins (1822–1891), U.S. Congressman
• Waldo P. Johnson (1817–1885), U.S. senator and Confederate congressman
• Waldo Kantor (born 1960), Argentine volleyball player
• Waldo K. Lyon (1914–1998), U.S. Navy physicist
• Waldo Machado (1934–2019), Brazilian former footballer
• Waldo McBurney (1902–2009), credited as "America's Oldest Worker"
• Waldo Ponce, Chilean football player
• Waldo de los Ríos (1934–1977), Argentine composer and conductor
• Waldo Salt (1914–1987), American screenwriter
• Waldo E. Sexton (1885–1967), American businessman
• Waldo Williams (1904–1971), Welsh language poet

Fictional characters

• Waldo, a central character in the Where's Wally? children's book series and television show
• Waldo, one of the Our Gang characters
• Waldo, a supporting character in the AMC series Into the Badlands
• "Waldo", nickname of the tourist guy in a 9/11 attack hoax photograph
• Waldo Faldo, a character from the television series Family Matters
• Waldo Farthingwaite-Jones, title character of "Waldo" (short story) by Robert A. Heinlein
• Waldo Jeffers, protagonist of The Velvet Underground song "The Gift"
• Waldo Jones, disabled inventor in Robert A. Heinlein's 1942 short story "Waldo"
• Waldo Kitty, a feline parody of Walter Mitty, from the animated series The Secret Lives of Waldo Kitty
• Waldo Magoo, the nephew of Quincy Magoo, from the Mr. Magoo franchise
• Waldo C. Graphic, a character from the theme park attraction Muppet*Vision 3D
• Waldo Pepper, title character of the film The Great Waldo Pepper
• Waldo Franz Schaeffer (more commonly known as Franz Hopper), a minor supporting character from the French animated television series Code Lyoko and its cancelled 2013 live-action/CGI show Code Lyoko: Evolution
• Uncle Waldo, the drunken gander from the 1970 Disney animated film The Aristocats
• Waldo, a Reptool in the television series Dinotrux
• Waldo Emerson Bell is the central character in K. M. Alexander's Bell Forging Cycle.