Education Secretary Nicky Morgan was heckled several times during a speech to the National Association of Head Teachers annual conference in Birmingham on Saturday.
She had been attempting to allay concerns over the government's the introduction of tougher tests for pupils and academy plans.
'Critical' primary school assesssments
Tougher spelling, grammar and punctuation tests for seven and 11-years-olds at Key Stage 1 and 2 have been brought in to raise standards but some parents and teachers are angry, claiming they are setting children up to fail.
A boycott of the SATs (Standard Assessment Tests) exams, which pupils in years Two, Six and Nine sit, has been planned for next week.
Ms Morgan also said she did not "accept the claim from some outside this hall, that the higher expectations embodied in the new national curriculum are somehow 'inappropriate"'.
"Virtually all children have the potential to become properly literate and numerate and I am unwilling, as I know you are, to settle for anything less."
Ms Morgan also defended the government's controversial academy plans.
If given the go-ahead in Parliament, 17,000 state-run schools in England will be forced to become autonomous academies run by trusts by 2022.
The announcement in a White Paper last month prompted a stream of protests across England, while two petitions against academisation have attracted around 300,000 signatures.
Morgan labels headteacher 'sexist'
During a question and answer session after her speech, Ms Morgan labelled a teacher "sexist" after he questioned whether she was really in charge of her department.
As part of a broader question, Simon Kidwell, headteacher of Hartford Manor Primary School in Cheshire, asked: "Are you in charge of the department or is Nick Gibb?"
The question was met with a round of applause from the headteachers, but Ms Morgan was not impressed.
She responded sharply: “I’m not going to dignify that sexist remark with a comment."
Russell Hobby, general secretary of the NAHT, said he believed the question stemmed from Mr Gibb's involvement in decision making in his capacity as Schools Minister but said he did not think Mr Gibb was running the department.
He also said he had "no idea" why Ms Morgan thought the question was sexist.
Christine Blower, general secretary of the National Union of Teachers, also said she could not see how the question could be classed as sexist and it was "completely valid".