NDP leader Andrea Horwath led her MPPs out of Question period, stressing that she can't ask questions to a premier who isn't there.
Kathleen Wynne was at a previously scheduled event in Sault-Ste-Marie.
Horwath stood up in her allotted time to ask a question and stormed out with the rest of the NDP caucus.
She wouldn't say if the gas plant email deletion scandal was enough for her to stop propping up the minority Liberals. Horwath and the NDP have been letting budgets pass since 2011.
Horwath also wouldn't commit to walking out of the legislature again if Wynne does not attend question period on another day this week.