Mathias Seger (born 17 December 1977) is a Swiss former professional ice hockey defenceman who played for the SC Rapperswil-Jona Lakers and the ZSC Lions of the National League (NL).

With the Swiss men's national team he won a silver medal at the 2013 World Championships.

[1] Seger was selected to play for the Switzerland men's national ice hockey team at the 2010 Winter Olympics.

[3] On 28 February 2017 Seger agreed to a one-year contract extension with the Lions for a reported worth of CHF 1.5 million.

After winning his sixth Swiss championship title with the ZSC Lions in 2018, he announced the end of his playing career.