Mark Thomas Streit (born 11 December 1977) is a Swiss former professional ice hockey defenceman.

In the 2007–08 season, he finished third in league scoring among defencemen, behind Nicklas Lidström and Sergei Gonchar, with 62 points in 81 games.

Streit was made the Canadiens' nomination for the Bill Masterton Trophy, awarded for perseverance and dedication to hockey.

[3] Coming off a breakout campaign, Streit became an unrestricted free agent on 1 July 2008, and signed a five-year, $20.5 million contract with the New York Islanders.

[4] Upon signing with the Islanders, Streit became the second-highest paid Swiss professional athlete, behind Roger Federer.

[7] On 25 September 2010, Streit tore his shoulder labrum and rotator cuff after a routine check into the boards by teammate Matt Moulson during a scrimmage.

[16] Although he began the season producing at a slower pace than before, he picked up by the second half and saw time on the Flyers' top power play unit.

[17] As the Flyers qualified for the 2014 Stanley Cup playoffs, Streit continued to man the second defence pairing with Nicklas Grossmann for their first round series against the New York Rangers.

[19] As a result of a long term injury to Kimmo Timonen, Streit stepped into a larger role on the Flyers top power play unit.

As a result of his productive season, Streit received the Barry Ashbee Trophy as the team's most outstanding defenseman and the Yanick Dupre Memorial Class Guy Award.

[26] After missing 19 games, Streit returned to Flyers lineup on 31 December for their 4–2 loss to the San Jose Sharks.

[30] Streit and the Flyers once again qualified for the Stanley Cup playoffs and faced off against the Washington Capitals in the first round.

The Tampa Bay Lightning then instantly traded him to the Pittsburgh Penguins for a fourth-round pick in the 2018 NHL Entry Draft.

[35] As injuries befell onto Justin Schultz and Trevor Daley, Streit continued to stay in the lineup.

Playing as the host nation, Switzerland finished a surprising fourth, falling to the Czech Republic in the bronze-medal game.

As Streit was named team captain at the 2006 Winter Olympics in Turin,[41] Switzerland improved to sixth, topping international giants Czech Republic and Canada in their preliminary games.