The 2003 Boston Red Sox season was the 103rd season in the franchise's Major League Baseball history. The Red Sox finished second in the American League East with a record of 95–67, six games behind the New York Yankees, who went on to win the AL championship. The Red Sox qualified for the postseason as the AL wild card and defeated the American League West champion Oakland Athletics in the ALDS. The Red Sox then lost to the Yankees in the ALCS.

The Red Sox led the major leagues in nearly all offensive categories, including runs scored (961), batting average (.289), on-base percentage (.360), and perhaps most impressively, a .491 team slugging percentage, which set a new record previously held by the 1927 Yankees. It would stand until the 2019 season when the Astros (.495) and Twins (.494) both surpassed them. They also had 649 extra-base hits, the most ever by one team in a single season.

In May 2003, the Red Sox settled a lawsuit in federal court filed by seven men who claimed to have been sexually abused as boys by Red Sox clubhouse attendant Donald James Fitzpatrick at the team's spring training site in Winter Haven, Florida between 1971 and 1991. The lawsuit requested $3.15 million in damages but the terms of the settlement were not disclosed.

This was the first season with designated hitter David Ortiz, as he signed a contract for the Red Sox during the offseason. He would stay with the Red Sox until his retirement in 2016.

The search for a new general manager Lucchino initially attempted to hire J. P. Ricciardi, the general manager of the Blue Jays, but Ricciardi rejected the offer and instead signed a long-term contract with the Blue Jays.

On November 10, 2002, Oakland Athletics General Manager, Billy Beane, accepted an offer to become the new general manager of the Red Sox. Beane had for several years publicly expressed his interest in joining the Red Sox, and his contract with Oakland included a stipulation that would allow Beane to consider an offer from the Red Sox. Beane had yet to sign the contract with the Red Sox, a contract in which he would be guaranteed $12.5 million over five years, the most anyone had been given to run a baseball team. The following day, however, Beane shocked the Red Sox when he declared that he would not accept their offer; the move to Boston would limit the amount of time that Beane would have to spend with his daughter.

On November 25, 2002, Theo Epstein, 28, was hired as general manager of the Boston Red Sox. Epstein's hiring made him the youngest general manager in major league history.

Offseason October 9, 2002: Brandon Lyon was selected off waivers by the Boston Red Sox from the Toronto Blue Jays.Brandon Lyon Statistics and History - Baseball-Reference.com November 6, 2002: Chris Coste signed as a free agent with the Boston Red Sox.Chris Coste Statistics – Baseball-Reference.com December 6, 2002: Wayne Gomes was released by the Boston Red Sox.Wayne Gomes Statistics and History - Baseball-Reference.com December 12, 2002: The Red Sox acquired second baseman Todd Walker from the Cincinnati Reds in exchange for two minor leaguers.Todd Walker Statistics and History - Baseball–Reference.com December 15, 2002: Jeremy Giambi was acquired by the Red Sox from the Philadelphia Phillies in exchange for pitcher Josh Hancock.Jeremy Giambi Statistics and History - Baseball-Reference.com December 31, 2002: Ramiro Mendoza signed as a free agent with the Boston Red Sox.Ramiro Mendoza Statistics – Baseball-Reference.com January 10, 2003: Bill Mueller was signed as a free agent with the Boston Red Sox.Bill Mueller Statistics and History - Baseball-Reference.com January 22, 2003: David Ortiz was signed as a free agent with the Boston Red Sox. February 15, 2003: Kevin Millar was purchased by the Boston Red Sox from the Florida Marlins.Kevin Millar Statistics and History - Baseball-Reference.com March 7, 2003: The Red Sox signed Shea Hillenbrand, Casey Fossum, Javier Lopez, Jorge de la Rosa, Brandon Lyon, Andy Shibilo, Anastacio Martínez, César Crespo, Earl Snyder, and Freddy Sanchez; released Juan Peña. March 10, 2003: The Red Sox optioned Jorge de la Rosa, Anastacio Martínez, Ángel Santos, César Crespo, and Freddy Sanchez to Pawtucket; assigned Kevin Youkilis and Hansel Izquierdo to minor-league camp. March 12, 2003: The Red Sox placed Benny Agbayani and Willie Banks on waivers. March 14, 2003: The Red Sox optioned Andy Shibilo to Pawtucket; assigned Justin Kaye, Kris Foster, Tom Davey, Kevin Tolar, Brian Loyd and Andy Dominique to minor-league camp. March 18, 2003: The Red Sox traded Javier López to Colorado for future considerations. March 21, 2003: The Red Sox assigned Earl Snyder, Julio Zuleta, and Lou Collier to minor-league camp. March 22, 2003: The Red Sox optioned Ryan Rupe to Pawtucket and returned Jeff Smith to minor-league camp for reassignment. March 26, 2003: The Red Sox waived Frank Castillo and returned Adrian Brown to Tampa Bay. March 28, 2003: The Red Sox claimed Dicky Gonzalez off of waivers from Montreal. March 30, 2003: The Red Sox designated Dicky Gonzalez for assignment and purchased Steve Woodard for assignment.

Regular season

Season standings

Record vs. opponents

+Red Sox vs. National LeagueTeamNL Central  CHCCINHOUMILPITSTLFLAPHIBoston——3–02–12–11–22–11–2

Notable transactions April 11, 2003: Bill Haselman signed as a free agent with the Boston Red Sox.Bill Haselman Statistics and History - Baseball-Reference.com May 29, 2003: Byung-Hyun Kim was acquired by the Red Sox from the Arizona Diamondbacks in exchange for Shea Hillenbrand.Byung-Hyun Kim Statistics and History - Baseball-Reference.com June 28, 2003: Gabe Kapler was purchased by the Boston Red Sox from the Colorado Rockies.Gabe Kapler Statistics – Baseball-Reference.com July 22, 2003: Scott Sauerbeck and Mike Gonzalez were acquired by the Red Sox from the Pittsburgh Pirates in exchange for Brandon Lyon and Anastacio Martínez.Scott Sauerbeck Statistics and History - Baseball-Reference.com July 30, 2003: Chad Fox was released by the Red Sox.Chad Fox Statistics and History - Baseball-Reference.com Scott Williamson was acquired by the Red Sox from the Cincinnati Reds.Scott Williamson Statistics and History - Baseball-Reference.com July 31, 2003: Freddy Sanchez and Mike Gonzalez were traded by the Boston Red Sox to the Pittsburgh Pirates for Jeff Suppan. The Red Sox also re-acquired Brandon Lyon and Anastacio Martínez.Freddy Sanchez Statistics and History - Baseball-Reference.com August 4, 2003: David McCarty was acquired off waivers by the Red Sox from the Oakland Athletics.Dave McCarty Statistics and History - Baseball-Reference.com August 28, 2003: Lou Merloni was acquired by the Red Sox from the San Diego Padres in exchange for minor league pitcher Rene Miniel.Lou Merloni Statistics and History - Baseball-Reference.com

Opening Day lineup 18 Johnny Damon CF12 Todd Walker 2B  5 Nomar Garciaparra     SS24 Manny Ramírez LF15 Kevin Millar 1B29 Shea Hillenbrand 3B25 Jeremy Giambi DH  7 Trot Nixon RF33 Jason Varitek C 45 Pedro Martínez P

Roster 2003 Boston Red Sox Roster Pitchers Catchers

Infielders Outfielders

Designated hitters Manager

Coaches (Pitching) (Third base) (Interim pitching) (Hitting) (Bullpen catcher) (Bench) (Bullpen) (Pitching) (First base)

Game log

|- style="background-color:#ffbbbb" | 1 || March 31 || @Devil Rays || 6–4 || McClung (1–0) || Fox (0–1) || — || 34,391 || 0–1

|- style="background-color:#bbffbb" | 2 || April 1 || @Devil Rays || 9–8 (16)|| Lyon (1–0) || Sosa (0–1) || — || 11,524 || 1–1 |- style="background-color:#bbffbb" | 3 || April 2 || @Devil Rays || 7–5 || Lowe (1–0) || Parque (0–1) || Fox (1) || 10,058 || 2–1 |- style="background-color:#bbffbb" | 4 || April 3 || @Devil Rays || 14–5 || Fossum (1–0) || Bierbrodt (0–1) || — || 12,110 || 3–1 |- style="background-color:#bbffbb" | 5 || April 4 || @Orioles || 8–7 || Burkett (1–0) || Ponson (0–1) || — || 27,256 || 4–1 |- style="background-color:#ffbbbb" | 6 || April 5 || @Orioles || 2–1 || Ryan (2–0) || Fox (0–2) || — || 41,821 || 4–2 |- style="background-color:#bbffbb" | 7 || April 6 || @Orioles || 12–2 || Wakefield (1–0) || López (0–1) || — || 30,046 || 5–2 |- style="background-color:#ffbbbb" | 8 || April 8 || @Blue Jays || 8–4 || Hendrickson (1–1) || Lowe (1–1) || — || 13,147 || 5–3 |- style="background-color:#ffbbbb" | 9 || April 9 || @Blue Jays || 10–5 || Sturtze (2–0) || Fossum (1–1) || — || 13,099 || 5–4 |- style="background-color:#bbffbb" | 10 || April 10 || @Blue Jays || 8–7 || Timlin (1–0) || Politte (0–1) || — || 13,779 || 6–4 |- style="background-color:#bbbbbb" | – || April 11 || Orioles || colspan=5|Postponed || 6–4 |- style="background-color:#bbbbbb" | – || April 12 || Orioles || colspan=5|Postponed || 6–4 |- style="background-color:#ffbbbb" | 11 || April 12 || Orioles || 13–6 || Johnson (1–0) || Martínez (1–1) ||—|| 32,029 || 6–5 |- style="background-color:#bbffbb" | 12 || April 13 || Orioles || 2–0 || Lowe (2–1) || López (0–2) || Wakefield (1) || 32,368 || 7–5 |- style="background-color:#bbffbb" | 13 || April 15 || Devil Rays || 6–5 || Timlin (2–0) || Levine (1–1) || — || 29,617 || 8–5 |- style="background-color:#bbffbb" | 14 || April 16 || Devil Rays || 6–4 || Fox (1–2) || Carter (3–1) || Lyon (1) || 26,688 || 9–5 |- style="background-color:#bbffbb" | 15 || April 17 || Devil Rays || 6–0 || Martínez (1–1) || Kennedy (0–1) || — || 30,909 || 10–5 |- style="background-color:#bbffbb" | 16 || April 18 || Blue Jays || 7–3 || Wakefield (2–0) || Tam (0–1) || — || 19,545 || 11–5 |- style="background-color:#bbffbb" | 17 || April 19 || Blue Jays || 7–2 || Derek Lowe (3–1) || Sturtze (2–1) || — || 32,329 || 12–5 |- style="background-color:#bbffbb" | 18 || April 20 || Blue Jays || 6–5 || Timlin (3–0) || Politte (0–2) || — || 29,579 || 13–5 |- style="background-color:#ffbbbb" | 19 || April 21 || Blue Jays || 11–6 || Lidle (3–2) || Burkett (1–1) || — || 34,370 || 13–6 |- style="background-color:#bbffbb" | 20 || April 22 || @Rangers || 5–4 || Martínez (2–1) || Park (1–3) || Fox (2) || 20,158 || 14–6 |- style="background-color:#ffbbbb" | 21 || April 23 || @Rangers || 6–1 || Thomson (1–2) || Wakefield (2–1) || — || 20,042 || 14–7 |- style="background-color:#ffbbbb" | 22 || April 24 || @Rangers || 16–5 || Dickey (1–1) || Lowe (3–2) || — || 21,063 || 14–8 |- style="background-color:#bbffbb" | 23 || April 25 || @Angels || 5–2 || Fossum (2–1) || Washburn (1–3) || Fox (3) || 37,203 || 15–8 |- style="background-color:#ffbbbb" | 24 || April 26 || @Angels || 3–1 || Shields (1–0) || Burkett (1–2) || Percival (3) || 43,514 || 15–9 |- style="background-color:#bbffbb" | 25 || April 27 || @Angels || 6–4 (14) || Mendoza (1–0) || Callaway (1–3) || Shiell (1) || 43,690 || 16–9 |- style="background-color:#bbffbb" | 26 || April 29 || Royals || 7–2 || Wakefield (3–1) || George (3–2) || — || 40,348 || 17–9 |- style="background-color:#bbffbb" | 27 || April 30 || Royals || 5–4 || Embree (1–0) || MacDougal (1–2) || — || 31,334 || 18–9

|- style="background-color:#bbffbb" ||28||May 1||Royals||6–5||Shiell (1–0)||Grimsley (1–2)||Lyon (2)||31,950||19–9 |- style="background-color:#ffbbbb" ||29||May 2||Twins||11–7||Santana (1–0)||Mendoza (1–1)||—||31,317||19–10 |- style="background-color:#bbffbb" ||30||May 3||Twins||9–1||Martínez (3–1)||Fiore (1–1)||—||33,061||20–10 |- style="background-color:#ffbbbb" ||31||May 4||Twins||9–4||Rogers (4–1)||Timlin (3–1)||—||32,887||20–11 |- style="background-color:#ffbbbb" ||32||May 5||@ Royals||7–6||Lopez (4–0)||Lyon (1–1)||—||21,232||20–12 |- style="background-color:#bbffbb" ||33||May 6||@ Royals||7–3||Fossum (3–1)||Affeldt (2–1)||—||15,848||21–12 |- style="background-color:#bbffbb" ||34||May 7||@ Royals||9–6||Woodard (1–0)||Lopez (4–1)||Lyon (3)||28,268||22–12 |- style="background-color:#ffbbbb" ||35||May 9||@ Twins||5–0||Santana (2–0)||Martínez (3–2)||—||28,436||22–13 |- style="background-color:#bbffbb"