Michael John Schreiner MPP (/ˈʃraɪnər/ ⓘ SHRY-nər; born 9 June 1969) is a Canadian politician who has served as the leader of the Green Party of Ontario since 2009.

[5] According to the Green Party of Ontario, he has served as a volunteer with organizations including FarmStart, the Brewer's Plate, the Toronto Food Policy Council and the Green Enterprise Ontario Steering Committee, the Canadian International Peace Project, and Toronto's Campus Community Co-op Day Care Centre.

[17] Despite not holding a seat in the legislature at that time, Schreiner lobbied in favour of the price on carbon, protecting pollinators with a ban on neonicotinoids, and funding for the Experimental Lakes Area.

In the 2011 election, Schreiner ran as a candidate for Simcoe—Grey, finishing fourth behind Progressive Conservative incumbent Jim Wilson.

In May 2018, the Toronto Star editorial board endorsed him as the best candidate in Guelph and said that he was "the most forthright leader in the campaign for the 7 June Ontario election".

[21] He captured 45 per cent of the vote in the Guelph riding, more than doubling the previous percentage and nearly tripling the actual number of voters for him.

[24] Just prior to the election, he told the CBC that he hopes to see Ontario moving to 100 per cent renewable energy and was in favour of closing the nuclear power plant at Pickering.

[25] Despite efforts to convince them otherwise, Schreiner was excluded from televised leaders debates, a move the Toronto Star billed as "unfair".

[28][29][30] As a party leader, Schreiner has been extensively quoted by the news media on issues such as the government's decisions to cancel the province's cap-and-trade legislation, scrapping the green energy programs and rebates, on the tactics used by Ford to reduce the size of Toronto City Council and on the provincial plan to allow marijuana smoking in numerous locations.

[10] During 2012 to 2017, he was a contributor to HuffPost Canada, on topics such as water protection, healthy food systems, recycling, climate change, clean tech, transit, energy and carbon pricing.

[34][35] Schreiner served on the steering committee for Green Enterprise Toronto, an association of over 350 small businesses, and on the Board of Directors of FarmStart, a non-profit that assists new farmers in Ontario, and he is a governor of the Canadian International Peace Project.