TORONTO -- Ontario's public high school teachers at select boards, including Toronto, have announced they will hold another one-day strike next week.

The Ontario Secondary School Teachers' Federation (OSSTF) announced on Friday that the Jan. 21 strike will affect nine school boards across the province.

The school boards affected by the strike include:

Toronto District School Board

Rainy River District School Board

Near North District School Board

Grand Erie District School Board

Brant Haldimand Norfolk Catholic District School Board

Simcoe County District School Board

Simcoe Muskoka Catholic District School Board

Trillium Lakelands District School Board

Hastings and Prince Edward District School Board

The OSSTF said the strike will be the last full withdrawal of services until after the high school exam period.

"Throughout this dispute we have made every effort to ensure that our job actions create minimal disruption for students," Bischof said in a statement on Wednesday.

“With that objective in mind, OSSTF/FEESO members will not engage in any work disruptions through the crucial exam period."

READ MORE: Ontario to give up to $60 a day to parents affected by ongoing school strikes