Primary schools to be built in areas including North Geelong, North Epping, Torquay and Mernda South are expected to open their doors in 2017 and 2018.
Eleven of the 12 will be built as part of a public private partnership (PPP), which will include a long-term facilities management contract.
Treasurer Michael O'Brien said the private sector will build and maintain the schools.
"Principals can worry about being educational leaders rather than worrying about sticky windows and blocked toilets," Mr O'Brien said on Tuesday.
"We want them to be focusing on quality education, not asset maintenance.
"This PPP model will deliver that."
The 12th school, not covered by the PPP model, is a $20 million secondary school for the inner-city suburb of Prahran, announced last month.
The money for the new schools is included in a $500 million allocation that will be spent on maintenance and further stages of upgrades and construction in growth areas including Doreen, in Melbourne's north, and Coburg.
The state government has also allocated $1.2 billion for vocational and education training.
Minister for Higher Education and Skills Nick Wakeling said the budget was centred around job-creating infrastructure.
"This significant investment provides support and access to training for people to develop the skills needed to take advantage of new opportunities emerging in the economy," Mr Wakeling said.