1969 Major League Baseball expansion

The 1969 Major League Baseball expansion resulted in the establishment of expansion franchises in Kansas City and Seattle in the American League and in Montreal and San Diego in the National League of Major League Baseball. The Kansas City Royals, Montreal Expos, San Diego Padres, and Seattle Pilots began play in the 1969 Major League Baseball season. One of the reasons for expansion was increasing pressure to maintain the sport as the US national pastime, particularly because of the increasing popularity of professional football.

As a result of expansion, the American and National Leagues reorganized. Each league was split into two divisions, forming the American League East, American League West, National League East, and National League West.

Other candidate cities that were considered in 1967 included Buffalo, Dallas–Fort Worth, and Milwaukee. The latter two were rejected because they were close to cities that already had a Major League Baseball team (Houston and Chicago, respectively). In May 1966, Commissioner of Baseball William Eckert stated that cities that should be considered for expansion included Milwaukee (the Milwaukee Braves had moved to Atlanta before the 1966 season), New Orleans, Oakland, San Diego, Seattle, and Toronto, and that expansion would occur in "eight to 10 years;" he subsequently stated that the leagues could expand "any time after two years". By August, Major League Baseball had plans to expand to two 12-team leagues by 1970, and had squelched the possibility of a third league, such as the Continental League proposed in 1959 or the proposal made in August 1968 by Ron Plaza consisting of an Eastern, Central, and Western League.