Michael E. Mantha^[1] is a politician in Ontario, Canada. He was elected as New Democratic member of the Legislative Assembly of Ontario until his removal from the Ontario NDP caucus on March 31, 2023, after which he sat as an independent. He was first elected in 2011. He represents the riding of Algoma—Manitoulin.

Prior to his election, Mantha was a staffer in the riding office of Carol Hughes, the federal Member of Parliament for Algoma—Manitoulin—Kapuskasing. He lives in Elliot Lake, Ontario with his wife Pauline and their two sons.^[2]

Mantha ran in the 2011 provincial election as the New Democratic candidate in the riding of Algoma—Manitoulin. He defeated Liberal incumbent Mike Brown by 4,188 votes.^[3][4] He was re-elected in the 2014 provincial election defeating Liberal candidate Craig Hughson by 7,668 votes.^[5] Mantha was re-elected in the 2022 Ontario general election.^[6]

He served the party's critic for a number of portfolios, including Northern Development and Mines, Indigenous Relations and Reconciliation^[7] and Northern Development and Tourism.^[8]

Mantha has introduced several pieces of important legislation, including a motion that was unanimously passed to create a lyme disease strategy in Ontario.^[9][10]

On April 1, 2023, Ontario NDP leader Marit Stiles removed Mantha from the caucus pending the results of an investigation into alleged misconduct involving a staffer. The decision was made after Stiles received an interim report on the allegations.^[11]

On August 15, 2023, Mantha was permanently removed from the NDP caucus after a third-party investigation found that the allegations of workplace misconduct levied against him were substantiated.^[12]