New strike dates have been announced after teachers from the National Education Union (NEU) overwhelmingly rejected a government pay offer.
Some 98% of members who voted rejected the offer, with strikes now scheduled for 27 April and 2 May.
The union had called the offer “insulting” and advised members to reject it.
It said it amounted to a £1,000 payment for the current school year and a 4.3% rise for most teachers next year.
The union’s analysis suggested between 42% and 58% of schools would have to make cuts to afford it.
The government said it was “a fair and reasonable offer” and “a good deal for teachers”.
The NEU is made up of teachers, further education lecturers, support staff and teaching assistants.