Dennis Wideman (born March 20, 1983 in Kitchener, Ontario) is a professional ice hockey defenceman who currently plays for the Boston Bruins of the National Hockey League.

Wideman was drafted from the London Knights of the Ontario Hockey League in the 8th round, 241st overall by the Buffalo Sabres in the 2002 NHL Entry Draft. He started the 2005–06 NHL season with the Peoria Rivermen of the American Hockey League but eventually got the call up to the St. Louis Blues and made his NHL debut on November 9, 2005 at Columbus.

Wideman played in 55 games for the Blues during the 2006–07 NHL season before being traded from the Blues to the Boston Bruins on February 27, 2007 for Brad Boyes. He finished with 25 points on the season.