The following are the baseball events of the year 2003 throughout the world.
Major League Baseball
- World Series: Florida Marlins over New York Yankees (4-2); Josh Beckett, MVP
- American League Championship Series: New York Yankees over Boston Red Sox (4-3); Mariano Rivera, MVP
- National League Championship Series: Florida Marlins over Chicago Cubs (4-3); Iván Rodríguez, MVP
- All-Star Game, July 15 at U.S. Cellular Field: American League, 7-6; Garret Anderson, MVP
- Caribbean World Series: Águilas Cibaeñas (Dominican Republic)
- College World Series: Rice
- European Championship: Netherlands over Greece (2-0)
- European Cup: Neptunus (Netherlands) over Rimini (Italy)
- Japan Series: Fukuoka Daiei Hawks over Hanshin Tigers (4-3)
- Little League World Series: Musashi-Fuchu, Tokyo, Japan
- Pan American Games: Cuba over USA (3-1)
Awards and honors
- Most Valuable Player
- Cy Young Award
- Rookie of the Year
- Manager of the Year Award
Major League Baseball final standings
|1st||New York Yankees||101||61||.623||--|
|2nd||Boston Red Sox *||95||67||.586||6.0|
|3rd||Toronto Blue Jays||86||76||.531||15.0|
|5th||Tampa Bay Devil Rays||63||99||.389||38.0|
|2nd||Chicago White Sox||86||76||.531||4.0|
|3rd||Kansas City Royals||83||79||.512||7.0|
|2nd||Florida Marlins *||91||71||.562||10.0|
|5th||New York Mets||66||95||.410||34.0|
|3rd||St. Louis Cardinals||85||77||.525||3.0|
|1st||San Francisco Giants||100||61||.621||--|
|2nd||Los Angeles Dodgers||85||77||.525||15.5|
|5th||San Diego Padres||64||98||.395||36.5|
- The asterisk denotes the club that won the wild card for its respective league.
- January 22 - David Ortiz is signed by the Boston Red Sox, where he will start a successful and productive career.
- April 3 - At 27 years, 249 days of age, Alex Rodriguez becomes the youngest player in major league history to hit 300 home runs. The Texas Rangers shortstop's fifth inning three-run blast surpasses Hall of Famer Jimmie Foxx's mark who had accomplished the feat at 27 years, 328 days of age.
- April 4 - Sammy Sosa hits his 500th career home run off Cincinnati Reds pitcher Scott Sullivan in the seventh inning at Great American Ball Park, becoming only the 18th player in major league history to hit 500 or more home runs, as well as the first Hispanic to do so.
- May 5 - Matt Stairs' home run off Houston Astros pitcher Wade Miller is estimated at 461 feet, making it the longest home run in the history of Minute Maid Park.
- May 11 - Rafael Palmeiro hits his 500th career home run off Cleveland Indians pitcher David Elder, becoming only the 19th player in major league history to reach the 500 mark.
- May 28 - Rafael Furcal, Mark DeRosa and Gary Sheffield hit home runs off Cincinnati Reds pitcher Jeff Austin in the bottom of the first inning, as the Atlanta Braves become only the second team in big league history to begin a game with three consecutive home runs. On April 13, 1987, the San Diego Padres' Marvell Wynn, Tony Gwynn and John Kruk did the same in the bottom of the first inning off San Francisco Giants starter Roger Mason.
- June 11 - The Houston Astros set a major league record for combined pitchers in a no-hitter with six, against the New York Yankees. The pitchers are Roy Oswalt, Pete Munro, Kirk Saarloos, Brad Lidge, Octavio Dotel and Billy Wagner.
- June 13 - Yankees pitcher Roger Clemens becomes the 21st pitcher in major league history to win 300 games and only the 3rd pitcher to record 4,000 career strikeouts as he defeats the St. Louis Cardinals 5-2.
- July 15 - At U.S. Cellular Field, the American League wins the All-Star Game, beating the National League 7-6. Hank Blalock connects for a two-run, pinch-hit home run off Eric Gagne in the eighth inning to lead the rally. Garret Anderson is named the MVP, coming just one triple shy of hitting for the cycle in going 3-for-4 with a home run and two RBI. Brendan Donnelly is the winning pitcher, while Keith Foulke gets the save.
- September 5 - Mike Maroth of the Detroit Tigers becomes the first major league pitcher in 23 years to lose 20 games in a season when Detroit loses to the Toronto Blue Jays 8-6. Maroth (6-20) allows eight runs and nine hits in three-plus innings. The Oakland Athletics' Brian Kingman went 8-20 in 1980.
- September 10 - The St. Louis Cardinals' Tony La Russa becomes the eighth manager in major league history to reach 2,000 wins as the Cardinals beat the Colorado Rockies 10–2. The 58-year-old La Russa has posted a 2,000-1,782 record in 25 seasons with the Chicago White Sox, Oakland Athletics and St. Louis.
- September 14 - At Comerica Park, the Detroit Tigers set a franchise record for losses as they drop their 110th loss to the Kansas City Royals, 7-2. The 1996 Tiger squad finished the season with a 53-109 record.
- September 17 - In the Boston Red Sox' 7-0 loss to the Tampa Bay Devil Rays, Todd Walker's ninth-inning double is the Red Sox's 608th extra base hit of the season, breaking the major league record set by the 1996 Seattle Mariners.
- September 20 - Unlike this season when the Montréal Expos played 25% of their home games in San Juan, Puerto Rico, the players vote to play their entire 2004 home schedule in Montreal. MLB owners, who collectively own the franchise, have been considering moving the Expos permanently to Washington, D.C., Portland, Oregon or Monterrey, Mexico, or continuing the present format by having the team split home games between different locations (Puerto Rico or Mexico and Montreal).
- September 20 - Second baseman Marcus Giles hits a home run off Brad Penny's 3-2 pitch, as the Atlanta Braves tie the NL record by having six players hit at least 20 home runs in a season. Along with Giles, Javy López, Gary Sheffield, Andruw Jones, Chipper Jones and Vinny Castilla equal the mark established by Eddie Mathews (32), Hank Aaron (32), Joe Torre (27), Felipe Alou (23), Mack Jones (31) and Gene Oliver (21) of the 1965 Milwaukee Braves.
- September 22 - The Detroit Tigers set an AL record with their 118th loss, falling 12-6 to the Kansas City Royals. The 1916 Philadelphia Athletics (36-117) had held the record.
- September 22 - Second baseman Alfonso Soriano breaks a major league season record by hitting his 13th leadoff home run of the year in the New York Yankees' 10-inning loss to the Chicago White Sox.
- October 14 - In Game 6 of the NLCS, with the Chicago Cubs just five outs away from eliminating the Florida Marlins, Cubs fan Steve Bartman deflects a foul fly ball away from Cubs left fielder Moisés Alou, allowing Florida's Luis Castillo to continue batting. The Cubs then proceed to fall apart, allowing eight runs in the inning to lose Game 6; they go on to lose Game 7, to continue the "Curse of the Billy Goat". The Marlins go on to win the World Series, and Bartman becomes a pariah in Chicago.
- October 25 - In Game 6 of the World Series at Yankee Stadium, Josh Beckett, on three days' rest, pitches a 2–0, five-hit shutout over the New York Yankees, to give the Florida Marlins their second championship in 11 seasons. Beckett receives MVP honors.
- Moneyball: The Art of Winning an Unfair Game, written by Michael Lewis, is an examination of the present-day Oakland Athletics as run by their general manager Billy Beane, and how the application of sabermetric principles has allowed the A's to be competitive despite having one of the lowest payrolls in baseball.
- January 9 - Don Landrum, 66, center fielder for four NL teams known for his speed
- January 11 - Durwood Merrill, 64, American League umpire from 1977 to 1999 who worked in the 1988 World Series, five ALCS, and two All-Star games
- January 14 - Earl Lawson, 79, sportswriter who covered the Cincinnati Reds from 1949 to 1985, often drawing criticism for his harsh commentary on players
- February 12 - Haywood Sullivan, 72, general manager of the Red Sox from 1977–84, previously a catcher and manager with the Kansas City Athletics
- February 17 - Steve Bechler, 23, pitching prospect who made three relief appearances for the 2002 Orioles
- March 14 - Al Gionfriddo, 81, outfielder who in his last major league game, Game 6 of the 1947 World Series, robbed Joe DiMaggio of a home run to preserve the Brooklyn Dodgers' 8-6 victory over the Yankees
- March 19 - Joe Buzas, 84, reserve shortstop for the 1945 Yankees who later operated 82 minor league franchises in his 47 years as an owner
- March 28 - Sam Bowens, 64, an outfielder who played for the Baltimore Orioles and Washington Senators from 1963 through 1969
- April 19 - Chris Zachary, 59, pitcher for five teams who posted a 1.41 ERA in relief for the 1972 Tigers
- May 6 - Art Houtteman, 75, All-Star pitcher who won 19 games for the 1950 Tigers and 15 for the 1954 Indians
- May 8 - Sam Lacy, 99, sportswriter for several decades in Washington, Chicago and Baltimore who championed the sport's integration and was one of the BBWAA's first black members
- June 1 - Johnny Hopp, 86, All-Star outfielder and first baseman who batted .300 five times with the Cardinals, Braves and Pirates
- June 18 - Larry Doby, 79, Hall of Fame center fielder for the Cleveland Indians, previously an All-Star second baseman in the Negro Leagues, who became AL's first black player in 1947; led AL in home runs twice, had five 100-RBI seasons; also a coach and scout
- June 22 - Leonard Koppett, 79, sportswriter and author who worked both in New York and on the West Coast
- July 27 - Bob Hope, 100, comedian and movie star who was part-owner of the Cleveland Indians in the 1950s; performed his signature song "Thanks for the Memory" in 1993 as the Indians ended 60 years of games at Municipal Stadium
- August 7 - Mickey McDermott, 74, pitcher who won 18 games for the 1953 Red Sox, but whose colorful personal life overshadowed his play
- August 9 - Billy Rogell, 98, shortstop for the Tigers' first World Series champions in 1935
- August 21 - Ken Coleman, 78, voice of the Boston Red Sox for 20 years, also with the Indians and Reds
- August 23 - Bobby Bonds, 57, All-Star right fielder for eight teams who recorded five of the first ten instances of hitting 30 home runs and stealing 30 bases in a season, ending career with 332 HRs and 461 steals; father of Barry Bonds
- August 30 - Claude Passeau, 94, 5-time All-Star pitcher for the Phillies and Cubs who led NL in strikeouts in 1939; pitched a one-hitter in Game 3 of the 1945 World Series
- September 14 - Allen Lewis, 86, sportswriter for the Philadelphia Inquirer for thirty years who also served twelve years as chairman of baseball's scoring rules committee
- September 25 - George Plimpton, 76, author whose forays into sports included pitching against the NL team prior to the second 1960 All-Star Game; wrote a fictitious story for Sports Illustrated in 1985 on "Sidd Finch", a phenomenal pitching prospect
- October 10 - Johnny Klippstein, 75, pitcher for eight teams who led AL in saves with the 1960 Indians
- October 12 - Joan B. Kroc, 75, owner of the Padres from 1984 to 1990 following the death of her husband, McDonald's founder Ray Kroc
- November 5 - Dernell Stenson, 25, promising young outfielder who had played 37 games in 2003 with the Cincinnati Reds
- November 6 - Spider Jorgensen, 84, third baseman who debuted with the Brooklyn Dodgers on the same day that teammate Jackie Robinson broke baseball's color barrier
- November 15 - Earl Battey, 68, All-Star catcher and three-time Gold Glove winner for the White Sox, Senators and Twins who batted .302 in 1961
- November 18 - Ken Brett, 55, All-Star pitcher for numerous teams who at age 19 became the youngest pitcher to appear in the World Series; brother of Hall of Famer George Brett
- November 24 - Warren Spahn, 82, Hall of Fame pitcher for the Boston and Milwaukee Braves whose 363 victories made him the fifth-winningest pitcher (and the winningest lefthander) in history; thirteen 20-win seasons included Cy Young Award campaign in 1957 championship season; 14-time All-Star pitched two no-hitters, and led NL in wins eight times, in strikeouts, shutouts and innings four times each, and in ERA three times; 2583 strikeouts were record for lefthanders until 1975, and 5244 innings remained top mark among southpaws
- December 26 - Paul Owens, 79, general manager of the Phillies from 1972 to 1984 who also managed the team to the 1983 pennant
- December 27 - Ivan Calderón, 41, Puerto Rican All-Star outfielder for four teams who had three multi-HR games for 1987 White Sox, batted .300 for 1991 Expos