Ayer is a surname. Notable people with the surname include:
- A. J. Ayer (1910âÂÂ1989), British philosopher
- Caleb Ayer (1813âÂÂ1883), American politician
- Claire D. Ayer (born 1948), Vermont politician
- David Ayer (born 1968), American screenwriter
- Donald B. Ayer (born 1949), United States Deputy Attorney General
- Edward E. Ayer (1841âÂÂ1927), American antiquarian and benefactor of Newberry Library and the Field Museum of Natural History
- Francis Ayer (1848âÂÂ1923), American advertising businessman
- Frederick Ayer (1822âÂÂ1918), American businessman
- Frederick Ayer Jr. (1915âÂÂ1974), American government official
- Harriet Hubbard Ayer (1849âÂÂ1903), American cosmetics entrepreneur and journalist
- Hilal Tuba Tosun Ayer (born 1970), Turkish female referee
- James Cook Ayer (1818âÂÂ1878), American patent medicine businessman
- Lewis Malone Ayer Jr. (1821âÂÂ1895), Confederate politician
- Nat Ayer (1887âÂÂ1952), British-American composer
- Richard S. Ayer (1829âÂÂ1896), U.S. Representative from Virginia