Entering the season as the three-time defending World Series champions, the Oakland Athletics' 1975 season involved the A's winning their fifth consecutive American League West title with a record of 98 wins and 64 losses. They went on to play the Boston Red Sox in the 1975 American League Championship Series, losing in three straight games.

Offseason

After the Athletics' victory over the Los Angeles Dodgers in the 1974 World Series under Alvin Dark, pitcher Catfish Hunter filed a grievance. He won the American League Cy Young Award in 1974 with a record of 25–12 and a league-leading 2.49 earned run average. Hunter uncovered a violation of his contract with A's owner Charlie Finley and the team that allowed him to become a free agent. The A's were to send half of Hunter's $100,000 annual salary to a North Carolina bank as payment on an annuity, but Finley did not comply. On December 13, 1974, arbitrator Peter Seitz ruled in Hunter's favor. As a result, Hunter became a free agent, and signed a contract with the New York Yankees for the 1975 season. Despite the loss of Hunter, the A's repeated as A.L. West champions in 1975, but lost the ALCS to Boston in a 3-game sweep. The Athletics led the league in arbitration filings with 13. Seven players settled before their hearings.

Notable transactions

Regular season

Relocation plans

Season standings

Record vs. opponents

Notable transactions

Roster

Player stats

Batting

Starters by position

''Note: Pos = Position; G = Games played; AB = At bats; H = Hits; Avg. = Batting average; HR = Home runs; RBI = Runs batted in''

Other batters

''Note: G = Games played; AB = At bats; H = Hits; Avg. = Batting average; HR = Home runs; RBI = Runs batted in''

Pitching

Starting pitchers

Note: G = Games pitched; IP = Innings pitched; W = Wins; L = Losses; ERA = Earned run average; SO = Strikeouts

Other pitchers

Note: G = Games pitched; IP = Innings pitched; W = Wins; L = Losses; ERA = Earned run average; SO = Strikeouts

Relief pitchers

Note: G = Games pitched; W = Wins; L = Losses; SV = Saves; ERA = Earned run average; SO = Strikeouts

Farm system