April 9, 2014: School Boards Collective Bargaining Act becomes law, separating negotiations into local and central talks.
Aug. 31, 2014: Contracts expire for teachers across Ontario.
April 17, 2015: Ontario Secondary School Teachers' Federation says their central talks with the province and the Ontario Public School Boards' Association are at an impasse.
April 20: Central talks with OSSTF resume.
April 20: High school teachers in Durham District School Board go on strike.
April 24: Ontario English Catholic Teachers' Association members vote 94 per cent for a strike mandate.
April 27: High school teachers in Rainbow District School Board go on strike.
May 4: High school teachers in Peel District School Board go on strike.
May 4: OSSTF says central talks are again at an impasse.
May 11: Elementary teachers begin a work-to-rule administrative strike.
May 12: Durham, Rainbow and Peel boards ask the Ontario Labour Relations Board to declare the strikes illegal, saying they are really over central, not local, issues.
May 14: Ontario Labour Relations Board hearing begins.
May 15: Minister of Education Liz Sandals asks the Education Relations Commission for advice on whether Durham, Rainbow, Peel students' school years are in jeopardy.
May 20: Central talks are set to resume with OSSTF.
May 21: High school teachers in Ottawa-Carleton District School Board and Halton District School Board are to begin an administrative strike.
May 23: OSSTF says talks have again reached an impasse and they are applying for conciliation.
May 25: The government tables back-to-work legislation for striking high school teachers in the Sudbury-area Rainbow District, Peel Region and Durham Region. The NDP does not support the bill.
May 26: Ontario Labour Relations Board declares the Rainbow, Peel and Durham strikes illegal.
May 27: High schools in the Durham, Rainbow and Peel districts reopen following the labour board ruling.
May 28: Ontario government passes back-to-work legislation, which ensures high school teachers in the Durham, Rainbow and Peel districts can't strike for the rest of the school year.