Heads' union the NAHT is today expected to announce its own ballot after it was revealed this week that the NUT and ATL had voted overwhelmingly in favour of going on strike.
The NAHT national executive was due to discuss what industrial action to take, with a strike being one of the options under consideration.
Speaking to The TES before the meeting, NAHT general secretary Russell Hobby said: "Our members did not need any more of a message about the other unions' support for strike action - the way they feel is already strong - but it will help to harden the views of some.
"We are feeling in a similar fashion to the other unions. We will have to put on our managers' hats while we deal with this strike, but we will be planning our own ballot timetable, depending on what our national executive decides."
NAHT vice-president Steve Iredale said: "We would be looking to ratchet up pressure on the Government pretty quickly. The anger among the leadership group of schools is strong, much bigger than over the Sats.
"I have no doubt at all that, if we were to ballot our members, we would get a very strong vote and a high turnout."
The ballot among NAHT members comes after union members voted for "any action necessary" to protect their pensions at their annual conference last month.
ATL members are to take to the picket line for the first time in the moderate union's 127-year history, after 83 per cent of those who voted backed the national strike, on a turnout of 35 per cent.
The NUT will also be striking, with 92 per cent of teachers in favour, on a turnout of 40 per cent.
ATL general secretary Mary Bousted described the ballot results as "a warning shot across the bows" of the Government.
The NUT general secretary Christine Blower said the "unnecessary attack on public sector pensions" had left teachers with "no alternative".
A Department for Education spokesman warned that a strike "will only damage pupils' learning and inconvenience their busy working parents".
The Government has proposed increasing pension contributions by 50 per cent, which would cost teachers an extra pound;1,145 per year on average.
The retirement age would also gradually rise to 68. The final salary scheme would be replaced by a career average.
Lord Hutton has also proposed that independent school teachers be excluded from the Teachers' Pension Scheme.
Dr Bousted said the anger among teachers in the private sector was "very notable and surprising". "While a one-day strike is regrettable, it is nothing compared to the wasteland that the Government's proposals are going to create in the profession," she said.
Members of the University and College Union, which represents college and university lecturers, will also strike on 30 June.
The NASUWT is waiting for the outcome of the next round of talks between the TUC and the Government on June 27 before deciding whether to ballot its members.