Mark Henry Belanger (June 8, 1944 – October 6, 1998), nicknamed "The Blade," was an American professional baseball player and coach.
He played 18 seasons in Major League Baseball as a shortstop from 1965 through 1982, most notably as a member of the Baltimore Orioles dynasty that won four American League pennants and two World Series championships between 1966 and 1971.
A defensive standout, Belanger won eight Gold Glove Awards between 1969 and 1978, leading the American League in assists and fielding percentage three times each; he retired with the highest career fielding average by an AL shortstop (.977).
Belanger set franchise records for career games, assists, and double plays as a shortstop, all of which were later broken by Cal Ripken Jr.
After his playing career, he became an official with the Major League Baseball Players Association.