Erin M. K. Weir is a Canadian politician from Saskatchewan. From 2015 until 2019, he was Member of Parliament for the riding of Regina—Lewvan. Weir initially sat as a member of the federal New Democratic Party (NDP) but was expelled from the party's caucus on May 3, 2018 after a dispute over a third party investigation that sustained some claims of harassment. No appeal of this investigation was granted. Before entering federal politics, Weir ran in the 2013 Saskatchewan New Democratic Party leadership election and was an economist with the Canadian section of the United Steelworkers union.