The following are the baseball events of the year 1973 throughout the world.
Major League Baseball 
Other champions 
Awards and honors 
MLB statistical leaders 
1 Modern single season strikeout record.
Major league baseball final standings 
American League final standings 
National League final standings 
- January 3 – A group of investors, headed by shipbuilder George Steinbrenner, purchases the New York Yankees from CBS for $10 million.
- January 18 – Orlando Cepeda signs with the Boston Red Sox, making him the first player signed by a team as a designated hitter.
- January 24 – Left-handed pitcher Warren Spahn is elected to the Hall of Fame in his first try on the Baseball Writers' Association of America ballot, receiving 316 of 380 votes.
- January 28 – The Hall of Fame Special Veterans Committee selects 19th-century pitcher Mickey Welch and Giants first baseman George Kelly, plus umpire Billy Evans, for enshrinement.
- February 1 – Commissioner Bowie Kuhn announces the selection of Monte Irvin for the Hall of Fame by the Special Committee on the Negro Leagues.
- February 27 – Chicago White Sox slugger Dick Allen signs a three-year contract for an estimated $250,000 per year, making him the highest-paid player in major league history.
- March 5 – New York Yankees teammates Fritz Peterson and Mike Kekich arrive at Spring training and announce that wives and families have been swapped. Even the family dogs were traded.
- March 20 – In a special election held by the Baseball Writers' Association of America, the late Roberto Clemente receives 393 of 424 votes to earn entry into the Hall of Fame. The Hall's Board of Directors had earlier waived the five-year-wait rule for Clemente.
- March 29 – Orange baseballs, the brainchild of Oakland Athletics owner Charlie Finley, are used in the Athletics' 11–5 exhibition loss to the Cleveland Indians.
- April 6:
- April 10 – The Kansas City Royals open their new park, Royals Stadium, with a 12–1 rout of the Texas Rangers. The game is attended by 39,464 fans braving 39-degree weather.
- April 17 – Philadelphia Phillies pitcher Dick Ruthven, signed from Fresno State, makes his major league debut without ever playing in the minor leagues. He starts against the Montreal Expos but doesn't finish, taking the loss in a 9–6 decision to Dick Selma.
- April 27 – In 50-degree weather, Kansas City Royals rookie Steve Busby no-hits the host Detroit Tigers 3–0. It is the first Royals no-hitter, and the first in Tiger Stadium since Virgil Trucks' in 1952. With the designated hitter rule in effect, Busby becomes the first pitcher of a no-hitter to not come to bat.
- May 8:
- May 9 – Johnny Bench of the Cincinnati Reds hit three home runs off Philadelphia's Steve Carlton for the second time in his career, in a 9–7 victory. Bench drove in seven runs.
- May 15 – Nolan Ryan of the California Angels pitches the first of his seven career no hitters, defeating the Kansas City Royals, 3–0.
- June 7 – Dave Winfield, the fourth pick in the June 1973 Major League Baseball Draft, will go straight to the major leagues with the San Diego Padres. Winfield was also taken in the NBA and NFL drafts. The Milwaukee Brewers use their third overall pick to select Robin Yount.
- June 9 – After the Old Timers' Game at Shea Stadium, Willie Mays puts on his own show with a home run and a circus catch, and the New York Mets top the Los Angeles Dodgers 4–2. For Mays, older than a half dozen of the old Mets, it is the 655th homer of his career. Rusty Staub drives in two runs to back Jon Matlack. In the Old Timers' Game, the Brooklyn Dodgers/New York Yankees team loses to the Mets 1–0 in two innings.
- June 13 – At Riverfront Stadium, St. Louis Cardinals pitcher Rick Wise loses a no-hitter when the Cincinnati Reds' Joe Morgan singles with one out in the ninth inning. It will be the only hit Wise allows in an 8–0 shutout win. Wise, who no-hit the Reds at Riverfront in 1971, was bidding to join Addie Joss as the only pitchers to throw two no–hitters against the same team.
- June 19 – In a Dodgers 4–0 victory over Cincinnati, Pete Rose (single) and Willie Davis (HR) each collect their 2,000th career hit.
- June 20:
- June 23 – Pitcher Ken Brett of the Philadelphia Phillies tops the Montreal Expos 7–2, and hits a home run for his fourth consecutive game, setting a major league record. Previously, Brett hit home runs on June 9, 13, and 18. He will total 10 for his career.
- June 28 – Willie Stargell hits his 300th career home run helping the Pittsburgh Pirates beat the St. Louis Cardinals 6–0.
- July 1 – Luis Aparicio of the Boston Red Sox steals the 500th base of his career in a 9–5 loss to the Milwaukee Brewers. It is the highest total in the American League since Eddie Collins retired in 1930.
- July 3 – Brothers Gaylord Perry (Indians) and Jim Perry (Tigers) pitch against each other for the only time in their careers. Neither finishes the game, but Gaylord is charged with the 5–4 loss. Two Norm Cash home runs help the Tigers.
- July 9 – In a record-setting walkathon between the Cincinnati Reds and Montreal Expos, 25 bases on balls are handed out as Montreal strolls to an 11–6 win. Well off the American League's two-team mark of 30, this tops the National League record of 23, last reached on July 7, 1911. Six Montreal pitchers walk 16, one short of the record for an NL team, while two Reds pitchers walk nine. Hal King pinch hits a grand slam for the Reds in the 6th inning, his second pinch homer in nine days.
- July 11:
- July 15:
- July 20 – Wilbur Wood starts both games of a doubleheader for the Chicago White Sox, and loses both games to the New York Yankees, 12–2 & 7–0.
- July 21 – Hank Aaron of the Atlanta Braves hits a Ken Brett fastball into the left-center field stands for a two-run home run during an 8–4 loss to the Philadelphia Phillies. It is career home run #700 for Aaron, only the second player to reach that milestone. Babe Ruth, with 714, is the other.
- July 24 – The National League wins the All-Star Game at Kansas City, 7–1. A record 54 players are used, including Willie Mays, who strikes out in his final All-Star appearance, and Catfish Hunter, who sustains a fractured thumb that will sideline him for four weeks. Hunter has a 15–3 record at the time.
- July 30 – At Oakland-Alameda County Coliseum, Jim Bibby of the Texas Rangers no-hits the Oakland Athletics 6–0. The no-hitter is the first in the history of the Washington Senators/Texas Rangers franchise.
- August 1 – With the score tied at 2–2 in the top of the ninth at Fenway Park, in an incident that typifies both the Yankees – Red Sox rivalry and the feud between the two catchers involved, Thurman Munson of the New York Yankees barrels into Carlton Fisk of the Boston Red Sox while trying to score on Gene Michael's missed squeeze attempt. The incident triggers a 10-minute bench-clearing brawl in which both catchers are ejected. The Red Sox win 3–2 in the bottom of the ninth, with Mario Guerrero's two-out single scoring Bob Montgomery (who had replaced the ejected Fisk) for the winning run.
- August 5 – Atlanta Braves knuckleballer Phil Niekro no-hits the San Diego Padres 9–0. He walks three and strikes out four in recording the first no-hitter by the franchise in Atlanta.
- August 6 – An exhibition game between the Milwaukee Brewers and the Atlanta Braves held at Milwaukee draws 33,337. The Brewers win, 7–5, in the fourth and last exhibition between the two teams. But the big thrill is provided by Hank Aaron, who hits a home run.
- August 7 – Two days after Phil Niekro's no-hitter, the Braves purchase Joe Niekro, Phil's pitching brother, from the Detroit Tigers.
- August 11 – Chicago White Sox rookie Brian Downing cracks his first major league hit, a home run off Detroit's Mickey Lolich. Downing's debut dinger is a first in the majors since at least 1945 – an inside-the-park homer. It'll be matched in two years by the Giants Johnnie LeMaster, who will do it in his first at bat.
- August 15 – In Pittsburgh, Cincinnati Reds ace Jack Billingham beats the host Pittsburgh Pirates 1–0, notching his seventh shutout of the season. This ties the club record set by Hod Eller back in 1919.
- August 17 – The New York Mets' Willie Mays hits the 660th (and last) home run of his career off Don Gullett of Cincinnati, but the Reds win 2–1 in 10 innings at Shea Stadium, after pinch hitter Hal King bats a walk-off home run, his third pinch homer of the year.
- August 21 - Against the Cleveland Indians at Cleveland Stadium, Stan Bahnsen of the Chicago White Sox has a no-hitter broken up with two out in the ninth on a single by ex-teammate Walt Williams. The hit is the only one Bahnsen allows as the White Sox defeat the Indians 4-0.
- September 3 – After 11 years at the helm (944–806 .539), Ralph Houk resigns as the New York Yankees' manager. The 'Major' will manage the Detroit Tigers next season.
- September 3 - The San Francisco Giants overcome a 7 - 1 deficit to beat the Los Angeles Dodgers 11 - 8 at Candlestick Park during a nationally televised Monday Night baseball game on NBC. Bobby Bonds hit a walk-off grand slam into the right field seats to win the game for the Giants.
- September 6 – Brothers Felipe Alou and Matty Alou are released by the New York Yankees. Felipe is sold to the Montreal Expos and Matty goes to the St. Louis Cardinals.
- September 19 – The Pittsburgh Pirates lose the first game of a crucial three game series at Shea for first place 7–3 to the New York Mets when Cleon Jones has just the second two home run performance of his career (the first time was on April 6, in the season opener against the Philadelphia Phillies).
- September 20 – At Shea Stadium, in the top of the thirteenth inning, with Richie Zisk on first, the Pittsburgh Pirates' Dave Augustine belted what appeared to be a home run over the left field wall. New York Mets left fielder Cleon Jones turned to play the ball off the wall and the ball hit the top of the wall and went right into Jones' glove on the fly. He turned and threw to relay man Wayne Garrett, who threw home to catcher Ron Hodges to nail Zisk at the plate. Following the "Ball on the Wall" play, the Mets won the game in the bottom half of the inning to move within half a game of the first place Pirates.
- September 27 – Capping a memorable season, Nolan Ryan strikes out 16 Minnesota Twins en route to a 5–4, 11 inning win for the California Angels. The final strikeout, his 383rd of the season, broke Sandy Koufax's season record.
- September 30 – The New York Yankees play their final game in the original Yankee Stadium, losing to the Detroit Tigers 5–2. Yankee Stadium remains closed until 1976 while undergoing major renovations.
- October 1 – Two make-up games were played after the scheduled end of the regular season on September 30: the Mets won at the Cubs 6–4 and the Pirates lost at home to the Padres 3–4, a possible second game between the Cubs and Mets was not necessary anymore.
- October 8 – In Game 3 of the National League Championship Series, the New York Mets' Rusty Staub homers in the first and second innings as the Mets crush the Cincinnati Reds 9–2 at New York's Shea Stadium, in a game featuring a bench-clearing brawl involving future Phillies teammates Pete Rose and Bud Harrelson.
- October 10 – Like 1969, no one thought the Mets would win the National League pennant, but they amazingly did as New York's Tom Seaver hurls the Mets into the World Series with a 7–2 victory over the Reds in Game 5 of the 1973 National League Championship Series. New York has 13 hits in the contest.
- October 13 – The Oakland Athletics score two unearned runs in the third inning of game one of the 1973 World Series when the usually sure handed Félix Millán allows a ground ball to go through his legs. They are the only runs New York Mets starter Jon Matlack allows, but they are enough to give Oakland the 2–1 game one victory.
- October 21 – Bert Campaneris and Reggie Jackson hit two-run home runs in the third inning as the Oakland Athletics defeated the New York Mets, 5–2, in Game Seven of the World Series, for their second straight World Championship. Jackson is selected the Series MVP.
- October 23 – Athletics owner Charlie Finley reveals that he will not release manager Dick Williams from his contract unless he receives adequate compensation from the team that signs him. Williams had resigned following the World Series victory two days earlier.
- November 27 – San Francisco Giants left fielder Gary Matthews, who hit .300 with 12 home runs and 58 RBI in 145 games, outpolls eight others receiving 11 of 24 nominations for the National League Rookie of the Year Award. The runner ups are Steve Rogers (P), Bob Boone (C), Dan Driessen (3B), Elías Sosa (P), Ron Cey (3B), Johnny Grubb (CF), Davey Lopes (2B) and Richie Zisk (RF).
- January 9 – Lyn Lary, 66, shortstop for seven teams who led AL in steals in 1936
- February 28 – Syl Simon, 75, infielder and pinch hitter for the Browns who played in the minor leagues after losing much of his left hand in an accident
- March 12 – Frankie Frisch, 74, Hall of Fame second baseman for the Giants and Cardinals who scored 100 runs seven times, led the NL in steals three times, and was the 1931 MVP; a lifetime .316 hitter, he twice batted .400 in the World Series, and also managed the Cardinals to the 1934 World Series title
- March 26 – George Sisler, 80, Hall of Fame first baseman for the St. Louis Browns widely recognized as the best defensive player ever at that position, he twice batted over .400 and hit .340 lifetime; the AL's 1922 MVP, he had a record 257 hits in 1920 and also led the league in steals four times
- April 13 – Clarence Blethen, 79, pitcher for the Boston Red Sox and Brooklyn Dodgers between 1923 and 1929
- May 19 – Jim Moore, 69, pitcher who played from 1928 to 1932 for the Cleveland Indians and Chicago White Sox
- June 11 – Bill Burwell, 78, pitcher for the St. Louis Browns in 1920–21, later a scout
- June 23 – Cliff Aberson, 51, two-sport athlete who was a left fielder for the Chicago Cubs from 1947 to 1949, and a halfback with Green Bay Packers in 1945
- July 2 – Chick Hafey, 70, Hall of Fame left fielder for the St. Louis Cardinals and Cincinnati Reds, a career .316 hitter who made the first hit in All-Star history and was the first batting champion to wear eyeglasses
- July 2 – George McBride, 92, shortstop for the Washington Senators known for his defense
- July 7 – Paul Musser, 84, pitcher for the Washington Senators (1912) and Boston Red Sox (1919)
- July 12 – Billy Urbanski, 70, shortstop for the Boston Braves from 1931 to 1936
- August 7 – Wilbur Cooper, 81, pitcher who won over 200 games for the Pittsburgh Pirates, he was the first NL left-hander to reach that milestone
- August 13 - Alva Jo Fischer, 46, All-American Girls Professional Baseball League pitcher and shortstop who earned inductions into several baseball halls of fame
- August 22 – George Cutshaw, 86, shortstop for the Dodgers, Pirates and Tigers who excelled on defense
- September 5 – Jack Fournier, 83, first baseman for five teams who hit .313 lifetime, led NL in homers in 1924
- September 10 – Roy Johnson, 70, outfielder who batted .300 four times and led AL in doubles and triples once each
- September 11 – Del Baker, 81, member of the Detroit Tigers organization for 28 years as a catcher, coach and manager, he led the team to the 1940 pennant
- September 14 – René Monteagudo, 57, Cuban pitcher and outfielder for the Senators and Phillies
- September 18 – Doug Smith, 81, pitcher for the 1912 Boston Red Sox
- October 8 – Ray Haley, 82, caught from 1915 through 1917 for the Boston Red Sox and Philadelphia Athletics
- October 22 – Ben Van Dyke, 85, pitcher for the Philadelphia Phillies (1909) and Boston Red Sox (1912)
- October 24 – Al Brazle, 60, pitcher who won 97 games for the St. Louis Cardinals, also leading the NL in saves twice
- October 27 – Bennie Tate, 71, catcher for the Washington Senators, Chicago White Sox, Boston Red Sox and Chicago Cubs between 1924 and 1934
- November 2 – Greasy Neale, 81, outfielder for the Cincinnati Reds who batted .357 in the 1919 World Series, but began coaching football to fill the time between baseball seasons
- November 15 – Phil Todt, 72, fine defensive first baseman who played from 1924 to 1931 for the Boston Red Sox and Philadelphia Athletics
- November 30 – Alex Metzler, 70, outfielder who hit .285 with a .374 OBP in 560 games for the Philadelphia Athletics, Chicago Cubs, Chicago White Sox, and St. Louis Browns from 1925 to 1930
- December 10 – Joe Riggert, 86, outfielder for four seasons in the major leagues; holds the record for career minor league triples