The following are the baseball events of the year 1940 throughout the world.  

Nicholas Altrock (September 15, 1876 – January 20, 1965) was an American left-handed pitcher in Major League Baseball.

Born in Cincinnati, Ohio, Altrock was one of the better pitchers in baseball for a brief period from 1904 to 1906 with the Chicago White Sox. He was instrumental in the White Sox World Series championship in 1906, going 20-13 with a 2.06 ERA in the regular season and 1-1 with a Series-best 1.00 ERA against the Chicago Cubs.

An arm injury after 1906 ruined his career, but he hung on with the White Sox and Washington Senators until 1924, though he pitched very little after 1908 and made sporadic pinch-hitting appearances after that, including one in 1933 (facing Rube Walberg of the Philadelphia Athletics) at 57 years of age. He appeared in Major League games in five decades, one of only two players to do this (Minnie Miñoso is the other); he is one of only 29 players in baseball history to have appeared in Major League games in four decades.

Altrock became a coach for the Senators in 1912 and remained on the Washington staff until 1953, a 42-year skein that represents the longest consecutive-year tenure of a coach with the same franchise in baseball history.

Willie Howard Mays, Jr. (born May 6, 1931) is a retired American professional baseball player who played the majority of his major league career with the New York and San Francisco Giants before finishing with the New York Mets. Nicknamed The Say Hey Kid, Mays was elected to the Baseball Hall of Fame in 1979, his first year of eligibility. Most baseball fans and historians agree that Mays was the greatest all-around baseball player to have played in the Major Leagues.

Mays won two MVP awards and tied Stan Musial's record with 24 appearances in the All-Star Game. Mays ended his career with 660 home runs, third at the time of his retirement, and currently fourth all-time. An outstanding center fielder, he won a record-tying twelve Gold Gloves starting the year the award was introduced six seasons into his career.

In 1999, Mays placed second on The Sporting News' List of the 100 Greatest Baseball Players, making him the highest-ranking living player. Later that year, he was also elected to the Major League Baseball All-Century Team. Mays is one of five NL players to have eight consecutive 100-RBI seasons, along with Mel Ott, Sammy Sosa, Chipper Jones and Albert Pujols. Mays hit 50 or more home runs in both 1955 and 1965. This time span represents the longest stretch between 50 plus home run seasons for any player in Major League Baseball history.

Ronald Edward Santo (February 25, 1940 – December 3, 2010) was an American professional baseball player, a member of the Baseball Hall of Fame and long-time radio sports commentator. He played in Major League Baseball from 1960 to 1974, most notably as the third baseman for the Chicago Cubs. A nine-time All-Star, he was a powerful hitter who was also a good defensive player, winning five Gold Glove Awards. Despite suffering from diabetes, he carefully concealed the condition for most of his career. The disease eventually necessitated the amputation of the lower half of both legs.

While Santo initially received little support for induction into the Baseball Hall of Fame, his standing among baseball enthusiasts and sabermetricians has gradually increased over time. On December 5, 2011, he was posthumously elected into the Baseball Hall of Fame by the Golden Era Committee.