William Penney, Baron Penney (1909–1991) was an English mathematician.

William Penney may also refer to:

• William Penney, Lord Kinloch (1801–1872), Scottish judge
• William F. Penney (1862–1934), Newfoundland judge and politician

• William Penny (1809–1892), Scottish whaling captain and explorer
• Will Penny, 1968 western film

This disambiguation page lists articles about people with the same name.
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