1961 Major League Baseball expansion

The 1961 Major League Baseball expansion was the formation of two new Major League Baseball (MLB) franchises that started in time for the 1961 season. The Los Angeles Angels and the Washington Senators were added to the American League (AL), becoming the 17th and 18th teams in MLB's two leagues. The expansion franchise in Los Angeles became the second MLB team in the city, after the Dodgers moved there from Brooklyn in 1958. The Senators replaced a previous franchise of the same name that moved to Minneapolis–St. Paul in 1961 and became the Minnesota Twins.

The expansion was part of an initiative that resulted in the addition of four clubs to MLB, in response to the threat of a proposed third major league, the Continental League. The following year the National League also added two new teams, the Houston Colt .45s (later named the Astros) and the New York Mets.

For a 50-year period from 1903 to 1952, MLB's 16-team (split into the American and National Leagues (NL)) structure remained intact. No franchises were relocated during this period, and five markets—Boston, Chicago, New York City, Philadelphia, and St. Louis—had two or more teams. According to authors Andy McCue and Eric Thompson, "The less financially successful clubs in two-team cities were finding it increasingly difficult to compete" by the early 1950s. In addition, population changes in the United States were leading to many citizens moving away from the Northeast, where many MLB teams were based, to southern and western locations.

From 1953 to 1955, three franchises were relocated, all of which had been in markets with two or more teams. Prior to the 1958 season, the two New York City teams in the NL—the Brooklyn Dodgers and New York Giants, moved westward; the Dodgers relocated to Los Angeles, while San Francisco became the new home of the Giants. New York City sought a replacement NL franchise, and by December 1958 MLB had created an Expansion Committee. Despite the formation of the group, MLB displayed little intention of adding a New York team.

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