Teachers are to form a new "super union" after members two unions voted to merge.
Members of the National Union of Teachers (NUT) and the Association of Teachers and Lecturers (ATL) backed the link-up by more than 2-1.
The National Education Union will be formed later in the year and will represent 450,000 teachers and other education workers.
It will be the biggest union in Europe for teachers and education professionals and the fourth biggest union in the UK.
Mary Bousted, general secretary of the ATL, said it was a "historic" moment, and that the new union will be the biggest in most schools, bringing together teachers, lecturers and managers.
She continued: "We will be able to do so much more working together."
NUT leader Kevin Courtney said: "For too long, governments have played divide and rule among education unions. Today marks the beginning of the end of that.
"The National Education Union will be a game-changer in the education landscape."