William Cobb may refer to:

• William Cobb (designer), designer and engineer of rollercoasters
• William H. Cobb, politician and father of baseball player Ty Cobb
• William J. Cobb, best known as Happy Humphrey, the heaviest professional wrestler of all time
• William Cobb (photographer), British photographer
• William T. Cobb (1857–1937), Governor of Maine, 1905–1909
• William Jelani Cobb (born 1969), American author and educator
• William Montague Cobb (1906–1990), physical anthropologist
• William Cobb (Eureka character), a character on the American science fiction drama Eureka
• William Peyton Cobb (1880–1963), Secretary of State of Alabama
• Will D. Cobb (1876–1930), American lyricist and composer
• Willie Cobb (fl. 1908–1909), American baseball player
• Billy Cobb (born 1940), English former footballer active in the 1960s
• William Cobb, a member of the Court of Owls.

• Bill Cobbs (1934–2024), American character actor