It's a one-day strike for public high school teachers in Niagara and across the province.
The Ontario Secondary School Teachers' Federation walked off the job after no deal was reached with the province before a midnight strike deadline.
Secondary schools in the District School Board of Niagara will be closed for student learning today.
The strike will also close all elementary and secondary schools in the French Public and Catholic boards.
The Niagara Catholic District School Board will operate as normal.
All staff and teachers not under the Ontario Secondary School Teachers' Federation are expected to report to work.
Classes will resume tomorrow.

Whales 'Holding Steady' at Marineland
Huge Donation Made to Hospital
School Bus Employee Charged by Police
Man Arrested After Child Porn Shared
Human Trafficking Session at Police Station
$10/Day Child Care Needed: MPP
Welland Man Charged with Child Porn
One Person Killed in Wainfleet Fire