Smoking will be banned around Victorian schools, hospitals, courts and police stations from April 13.
Smokers caught lighting up within four metres of a building where the ban applies face an on-the-spot fine of $147.
The ban also applies to kindergartens, childcare centres, hospitals and maternal child and welfare facilities.
The ban had been scheduled to start in July, but Health Minister Jill Hennessy said it was being brought forward to coincide with the start of the school term.
"Every year in Victoria we lose 4,000 people to smoking," she said.
"Smoking-related illnesses cost the health budget about $2.4 billion and that's why I'm delighted today that we've decided to bring changes forward."
The move also has the support of Education Minister James Merlino.
"Kids are impressionable and we don't want them to see behaviour that normalises smoking," he said.
"Having it banned in front of the entrances to schools is an important step.
"The incidence of smoking in schools is going down but we want it go down even further and an important step in achieving that is ensuring that when kids come into school they don't see people smoking in front of school."