The following are the baseball events of the year 1903 throughout the world.  

Denton True "Cy" Young (March 29, 1867 – November 4, 1955) was an American Major League Baseball pitcher. During his 22-year baseball career (1890–1911), he pitched for five different teams. Young established numerous pitching records, some of which have stood for a century. Young compiled 511 wins, which is most in Major League history and 94 ahead of Walter Johnson who is second on the list. Young was elected to the National Baseball Hall of Fame in 1937. One year after Young's death, the Cy Young Award was created to honor the previous season's best pitcher.

In addition to wins, Young still holds the Major League records for most career innings pitched (7,355), most career games started (815), and most complete games (749). He also retired with 316 losses, the most in MLB history. Young's 76 career shutouts are fourth all-time. He also won at least 30 games in a season five times, with ten other seasons of 20 or more wins. In addition, Young pitched three no-hitters, including the third perfect game in baseball history, first in baseball's "modern era". In 1999, 88 years after his final Major League appearance and 44 years after his death, editors at The Sporting News ranked Cy Young 14th on their list of "Baseball's 100 Greatest Players". That same year, baseball fans named him to the Major League Baseball All-Century Team.

Tyrus Raymond "Ty" Cobb (December 18, 1886 – July 17, 1961), nicknamed "The Georgia Peach," was an American Major League Baseball outfielder. He was born in Narrows, Georgia. Cobb spent 22 seasons with the Detroit Tigers, the last six as the team's player-manager, and finished his career with the Philadelphia Athletics. In 1936, Cobb received the most votes of any player on the inaugural Baseball Hall of Fame ballot, receiving 222 out of a possible 226 votes.

Cobb is widely credited with setting 90 Major League Baseball records during his career. He still holds several records as of 2012, including the highest career batting average (.366 or .367, depending on source) and most career batting titles with 11 (or 12, depending on source). He retained many other records for almost a half century or more, including most career hits until 1985 (4,189 or 4,191, depending on source), most career runs (2,245 or 2,246 depending on source) until 2001, most career games played (3,035) and at bats (11,429 or 11,434 depending on source) until 1974, and the modern record for most career stolen bases (892) until 1977. He committed 271 errors in his career, the most by any American League outfielder.

Pablo Diego José Francisco de Paula Juan Nepomuceno María de los Remedios Cipriano de la Santísima Trinidad Ruiz y Picasso, known as Pablo Picasso (Spanish pronunciation: [ˈpaβlo piˈkaso], 25 October 1881 – 8 April 1973), was a Spanish painter, sculptor, printmaker, ceramicist, and stage designer who spent most of his adult life in France. One of the greatest and most influential artists of the 20th century, he is widely known for co-founding the Cubist movement, the invention of constructed sculpture, the co-invention of collage, and for the wide variety of styles that he helped develop and explore. Among his most famous works are the proto-Cubist Les Demoiselles d'Avignon (1907), and Guernica (1937), a portrayal of the German bombing of Guernica during the Spanish Civil War.

Picasso, Henri Matisse and Marcel Duchamp are commonly regarded as the three artists who most defined the revolutionary developments in the plastic arts in the opening decades of the 20th century, responsible for significant developments in painting, sculpture, printmaking and ceramics.