Brian O'Nora (born February 1963 in Youngstown, Ohio) is an umpire in Major League Baseball. He joined the major league staff in 1999 and wears uniform number 7.
O'Nora previously worked the Appalachian League (1985), the Midwest League (1986-1987), the Eastern League (1988-1989), the Pacific Coast League (1990), the Americam Association (1991), the International League, the Florida Instructional League (1985-1989) and the Puerto Rican Winter League (1990-1992).
Since joining the Major League umpiring staff in 1999, O'Nora has worked the 2004 National League Division Series and the 2006 National League Division Series. He was a part of the crew that worked in the 2000 Major League Baseball All-Star Game.