Baer (or Bär, from ) is the surname of:

• Arthur "Bugs" Baer (1886–1969), American journalist and humorist
• Buddy Baer (1915–1986), American boxer
• Byron Baer (1929–2007), American politician
• Clara Gregory Baer (1863–1938), inventor of Netball, Newcomb ball and author of first rules of women's basketball
• Donald Baer (1931–2002), American Developmental Psychologist
• Eric Baer, polymer researcher
• George Baer, Jr. (1763–1834), American politician
• George Frederick Baer (1842–1914), American lawyer and executive
• Gregory S. Baer (born 1952), American lecturer and physician
• Harold Baer, Jr. (1933–2014), American judge
• Jack Baer (1914–2002), American college baseball coach
• John Baer (actor) (1923–2006), American actor in Terry and the Pirates and other works
• John Baer (journalist), American journalist at the Philadelphia Daily News
• John Metz Baer, American professor of educational psychology
• John Miller Baer (1886–1970), American congressman from North Dakota
• John Willis Baer (1861–1931), American Presbyterian leader and college president
• Julius Baer (1857–1922), Swiss banker
• Karl Ernst von Baer (1792–1876), Estonian biologist
• Kent Baer (born 1951), American football coach
• Les Baer, founder of Les Baer Custom, Inc
• Max Baer (boxer) (1909–1959), American boxer
• Max Baer, Jr. (born 1937), American actor and director
• Nicolai Reymers Baer, aka Ursus (c. 1550 – c. 1600), German mathematician
• Susanne Baer (born 1964), German judge and legal scholar
• Parley Baer (1914–2002), American actor
• Ralph H. Baer (1922–2014), American inventor
• Reinhold Baer (1902–1979), German mathematician
• Richard Baer (Nazi) (1911–1963), German Nazi officer
• Richard Baer (writer) (1928–2008), American screenwriter
• Robert Baer (born 1952), former CIA officer and American writer
• Steve Baer (born 1938), American inventor
• Thomas M. Baer, American physicist
• Will Christopher Baer (born 1966), American writer
• William Jacob Baer (1860–1941), American painter
• Yitzhak Baer (1888–1980), German-born Israeli historian

The auditory brainstem response (ABR) is an auditory evoked potential extracted from ongoing electrical activity in the brain and recorded via electrodes placed on the scalp. The resulting recording is a series of vertex positive waves of which I through V are evaluated. These waves, labeled with Roman numerals in Jewett and Williston convention, occur in the first 10 milliseconds after onset of an auditory stimulus. The ABR is considered an exogenous response because it is dependent upon external factors.