The Plymouth Whalers were a major junior ice hockey team in the Ontario Hockey League. They played out of Compuware Arena in Plymouth, Michigan, United States, a suburb of Detroit until 2015 when they were relocated to Flint, Michigan.

The Whalers can trace their roots back to the 1990–91 Detroit Compuware Ambassadors as an expansion team in the OHL. Since then the franchise has also been called the Detroit Junior Red Wings and the Detroit Whalers. In 1997 they were officially renamed the "Plymouth Whalers" after the local municipality gave generous tax breaks to the team and venue. The franchise was owned until 2015 by Peter Karmanos, who also owned the NHL's Carolina Hurricanes (formerly the Hartford Whalers, from which the OHL team's name was taken).

Plymouth is one of only two teams to win 5 consecutive division titles (West division from 1999 to 2003), the other team being the Ottawa 67's (East division from 1996 to 2000). Plymouth has made the playoffs 23 consecutive seasons, since the 1991–92 season. The Whalers reached the OHL finals two consecutive seasons in 1999–2000, and 2000–01, losing to the Barrie Colts and Ottawa 67's. These seasons included future NHLers David Legwand, Justin Williams, Robert Esche, and Stephen Weiss.

Celebrating their 10th Anniversary playing at the Compuware Arena during the 2005–06 season, all current Whalers players had been brought into the system by head coach and general manager Mike Vellucci. This created the build-up for the next year. Headed by overage captain John Vigilante, the team's rookies in 2003 and 2004 came to fruition in James Neal, Dan Collins, and Tommy Sestito. Vellucci acquired the Belleville Bulls' leading scorer Evan Brophey and the Toronto St. Michael's Majors goaltender Justin Peters, who had an extensive resume. On the last game of the season, the Whalers played the Saginaw Spirit, with the division title on the line, in what has been proven to be one of the most exciting OHL games in recent history. With the Whalers' 2–0 lead going into the third period, the Spirit fought back and managed the tying goal just before time expired. However, Brophey scored in overtime to clinch the Whalers' 9th division title.

During the 2006–07 season, rookie goaltenders Jeremy Smith and Michal Neuvirth, combined for the lowest goals against average in the OHL, with only 173 goals against in total. The Whalers had a number of high prospects signed or drafted by NHL teams, including former Wayne Gretzky 99 Award winner Daniel Ryder, who was acquired, with him already having been signed with the Calgary Flames. After a very inconsistent start, the team improved to fall short of the London Knights by one point for the Hamilton Spectator Trophy. During the second half of the season and through the playoffs, the Whalers featured a 23-game winning streak at home, lasting three and a half months, falling at Game 4 of the Western Conference Finals to London. The Whalers, although seeded #2, easily won the Wayne Gretzky Trophy as Western Conference playoff champion, sweeping #7 Guelph, and winning in 5 against both #3 Kitchener and #1 London. In the final, the Whalers defeated the Sudbury Wolves in six games to win the J. Ross Robertson Cup, thus earning the right to represent the OHL in the 2007 Memorial Cup.

In the Memorial Cup, the team suffered a rough start, losing to the Vancouver Giants 4–3 in overtime on May 18, and again to the Medicine Hat Tigers 4–1 on May 21. Their fortunes would change, however, on May 22, when they would defeat the Lewiston Maineiacs 2–1 in overtime, thus putting them in the tiebreaker game on May 24, in which they would defeat Lewiston again, 5–1, eliminating the Maineiacs from the Memorial Cup and advancing to the semifinal. However, on May 25, the Whalers would lose again to the Vancouver Giants in the semifinal round, this time in dramatic fashion by a score of 8–1. This way, the Whalers finished the 2007 Memorial Cup in third place.

During the 2007–08 season, the Whalers dealt the goaltender that led them to their 2007 OHL Championship, Michal Neuvirth, early to make room for Jeremy Smith to start. Neuvirth was among 12 players that left/were traded from that team, leaving the team looking to a number of young players for leadership. Chris Terry led the team in scoring and was helped by overage captain Andrew Fournier and up-and-comer AJ Jenks. In mid-December 2007, President and GM Mike Vellucci left his head coaching position for Greg Stefan. A late season injury to overage defenseman Wes Cunningham hampered the flow of the team, leading to an early playoff exit at the hands of the eventual OHL champions, the Kitchener Rangers.

Early in the 2008–09 season, Stefan was recalled to the Hurricanes, where Mike Vellucci came back to fill the head coaching role. Injuries and inconsistency plagued the team, as they fell to dead last in the league. After the coaching change, as well as key trades, including a short lived experiment with Cory McGillis, then-leading scorer Matt Caria from the Greyhounds, Scott Fletcher from the Ice Dogs, and the return from AHL-playing Brett Bellemore, the team saw a turn around by Christmas putting them back into the middle of the pack. At the deadline, as a result of Bellemore's return and the emergence of Matt Hackett as the new starting goaltender, Patrick Lee and Jeremy Smith were traded to Niagara for draft picks.