15 teams are tied for the most grand slams in a game in the 12th inning, with 1 grand slam. The first three are the Seattle Mariners on April 19, the Oakland Athletics on July 12, 2022 and on June 8, 2008 and the Tampa Bay Rays on May 21, 2021.
Interpreted as:
team most grand slam in a regular-season game in the 12th inning| TEAM | GRANDSLAM | DATE | TM | OPP | AB | H | 2B | 3B | HR | RBI | BB | HBP | SO | PA | TB | XBH | SH | SF | IBB | AVG | OBP | SLG | OPS | |||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 |  | Mariners | 1 | 4/19/2025 |  SEA | @ |  TOR | 6 | 3 | 0 | 0 | 1 | 5 | 2 | 0 | 1 | 8 | 6 | 1 | 0 | 0 | 0 | .500 | .625 | 1.000 | 1.625 |
| 2 |  | Athletics | 1 | 7/12/2022 |  OAK | @ |  TEX | 5 | 3 | 1 | 0 | 1 | 8 | 4 | 0 | 0 | 10 | 7 | 2 | 0 | 1 | 1 | .600 | .700 | 1.400 | 2.100 |
| 3 |  | Rays | 1 | 5/21/2021 |  TBR | @ | TOR | 4 | 1 | 0 | 0 | 1 | 4 | 2 | 0 | 1 | 6 | 4 | 1 | 0 | 0 | 2 | .250 | .500 | 1.000 | 1.500 |
| 4 |  | Tigers | 1 | 9/14/2019 |  DET | vs |  BAL | 3 | 2 | 1 | 0 | 1 | 5 | 3 | 0 | 1 | 6 | 6 | 2 | 0 | 0 | 1 | .667 | .833 | 2.000 | 2.833 |
| 5 |  | White Sox | 1 | 5/9/2016 |  CWS | @ | TEX | 6 | 3 | 1 | 0 | 1 | 4 | 2 | 0 | 1 | 8 | 7 | 2 | 0 | 0 | 1 | .500 | .625 | 1.167 | 1.792 |
| 6 | | Athletics | 1 | 6/8/2008 | OAK | vs |  LAA | 5 | 3 | 0 | 0 | 1 | 4 | 1 | 0 | 1 | 6 | 6 | 1 | 0 | 0 | 0 | .600 | .667 | 1.200 | 1.867 |
| 7 | | Tigers | 1 | 4/11/2007 | DET | @ |  BAL | 7 | 4 | 0 | 0 | 1 | 4 | 1 | 0 | 1 | 8 | 7 | 1 | 0 | 0 | 0 | .571 | .625 | 1.000 | 1.625 |
| 8 |  | Twins | 1 | 6/13/2006 |  MIN | vs |  BOS | 3 | 2 | 1 | 0 | 1 | 4 | 1 | 1 | 1 | 5 | 6 | 2 | 0 | 0 | 1 | .667 | .800 | 2.000 | 2.800 |
| 9 |  | Reds | 1 | 9/4/2005 |  CIN | @ |  ATL | 7 | 4 | 1 | 0 | 1 | 5 | 1 | 0 | 1 | 8 | 8 | 2 | 0 | 0 | 1 | .571 | .625 | 1.143 | 1.768 |
| 10 |  | Expos | 1 | 8/3/2004 |  MON | @ |  STL | 3 | 1 | 0 | 0 | 1 | 4 | 3 | 0 | 0 | 7 | 4 | 1 | 1 | 0 | 1 | .333 | .667 | 1.333 | 2.000 |
| 11 |  | Diamondbacks | 1 | 5/9/2000 |  ARI | vs |  LAD | 3 | 3 | 0 | 0 | 1 | 5 | 1 | 1 | 0 | 6 | 6 | 1 | 0 | 1 | 0 | 1.000 | .833 | 2.000 | 2.833 |
| 12 |  | Indians | 1 | 9/6/1992 |  CLE | vs |  SEA | 5 | 3 | 1 | 0 | 1 | 5 | 2 | 0 | 0 | 7 | 7 | 2 | 0 | 0 | 1 | .600 | .714 | 1.400 | 2.114 |
| 13 |  | Phillies | 1 | 9/17/1989 |  PHI | vs | STL | 5 | 3 | 0 | 0 | 1 | 4 | 1 | 0 | 1 | 6 | 6 | 1 | 0 | 0 | 0 | .600 | .667 | 1.200 | 1.867 |
| 14 |  | Rangers | 1 | 6/1/1987 |  TEX | vs |  CWS | 3 | 2 | 1 | 0 | 1 | 4 | 2 | 0 | 0 | 5 | 6 | 2 | 0 | 0 | 0 | .667 | .800 | 2.000 | 2.800 |
| 15 |  | Braves | 1 | 5/27/1986 | ATL | @ |  PIT | 5 | 2 | 0 | 0 | 1 | 4 | 2 | 0 | 0 | 7 | 5 | 1 | 0 | 0 | 1 | .400 | .571 | 1.000 | 1.571 |
| 16 | | Indians | 1 | 7/29/1982 | CLE | @ |  MIL | 6 | 4 | 0 | 0 | 1 | 4 | 2 | 0 | 0 | 9 | 7 | 1 | 1 | 0 | 0 | .667 | .750 | 1.167 | 1.917 |
| 17 |  | Pirates | 1 | 6/24/1978 | PIT | @ |  NYM | 7 | 5 | 0 | 0 | 1 | 5 | 2 | 0 | 1 | 10 | 8 | 1 | 1 | 0 | 2 | .714 | .778 | 1.143 | 1.921 |
| 18 |  | Royals | 1 | 6/25/1975 |  KCR | @ |  CAL | 5 | 3 | 0 | 0 | 1 | 4 | 3 | 0 | 0 | 8 | 6 | 1 | 0 | 0 | 0 | .600 | .750 | 1.200 | 1.950 |
Results may be incomplete. StatMuse has complete event-level data for grand slams going back to the 1974 season.
Some of the information used here was obtained free of charge from Retrosheet.
Astros 
Yankees 
Twins 
Phillies 
Cubs 
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COL 
SFG 
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