The Ontario provincial electoral districts each elect one representative to the Legislative Assembly of Ontario. They are MPPs, Members of Provincial Parliament. Before 2025, these districts were coterminous with the federal electoral districts, based on the 2013 Representation Order as defined by Elections Canada. The exception was Northern Ontario, whose districts were not equivalent to their federal complements, since the provincial government did not want to decrease the number of districts in Northern Ontario. Despite Ontario's federal ridings changing substantially in the 2022 Canadian federal electoral redistribution, the provincial ridings remained unchanged, leading to Ontario's provincial and federal ridings once again being separate as of the 2025 provincial and federal elections.
The following 124 electoral districts are currently represented in the Legislative Assembly of Ontario. The average riding population was 108,482 as of 2016.