Ms Parata said she advised Prime Minister John Key of her decision earlier this year.
Otago Secondary Principals' Association secretary Gordon Wilson said the sector was genuinely surprised by the announcement.
''Always around election time, there are often changes where incumbent ministers move to other portfolios. Things change.
''It certainly wasn't something that we had expected [from Ms Parata].''
Otago Primary Principals' Association chairman Hamish McDonald said there had been several ministers of education during his career, and each brought different skills to the portfolio, while delivering the direction of the government.
Both Mr Wilson and Mr McDonald said the sector was now looking forward to working with the minister who would replace Ms Parata.
Ms Parata said it was the right decision for her and her family, and it was the right time to make her intentions known.
''I have no plans beyond serving as Education Minister, as long as the Prime Minister wishes me to.''
She said there were still ''a number of deliverables'' in the education work plan in the meantime, and her focus and energy would be ''unwavering''.
She was keen to see a fresh candidate nominated in the Mana seat, who would provide voters with a strong contest at the next election.
