More than 11,000 teachers who work for the Toronto District School Board are being told by their union to prepare for a one-day walkout next Tuesday.
The TDSB said Thursday it is preparing for the strike, though it is still waiting for the required 72-hour notice from the Elementary Teachers' Federation of Ontario.
The board says in a message on its website that it "expects to receive official notification from ETFO in the near future."
More than 184,000 students could be affected by the strike.
The board has already warned parents it will close all schools and that other child care arrangements should be made.
Daycares inside schools will not be affected.
"ETFO has been in a legal strike position since December 10, 2012 and has directed elementary school teachers not to participate in field trips, play days, class excursions or voluntary and extra-curricular activities," said the TDSB.
The root of the problem is the passage of Bill 115 by the province's Liberal minority government.
The teachers say the legislation — which will impose new contracts on most of the province's teachers in January — takes away their bargaining rights, reduces benefits and freezes wages.
The Liberals have said they will not interfere in the one-day strikes as long as proper (72-hour) warning is given to parents and schools.