The government was criticised for breaking its pledge to leave funding for education intact, after the financial secretary announced a 3.7 per cent spending cut.
Education will receive $56.5 billion in the coming financial year, down from $58.6 billion.
The recurrent budget, which provides funding for continuing initiatives, has dropped from last year's $49.1 billion to $47.8 billion this year.
Vivian Lau Lee-kwan, deputy secretary for education and manpower, attributed the $2.1 billion overall drop to the construction of fewer schools and the near-completion of the school-improvement project.
Ms Lau said funding remained unchanged in all other areas expect those.
Legislator Cheung Man-kwong, chairman of the Professional Teachers' Union, said he was disappointed with the reduction in the recurrent budget.