The registrar of voters said 5,062 people turned out for Saturday's referendum, the highest turnout since the 2008 presidential election.
"I'm very happy that it passed, and passed significantly," said Legislative Council Chairman Jeff Capeci. "I had a feeling it would. Now we can move forward with the new school. This is great for the town. We can bring our children home."
Of the voters, 4,504 said yes to the referendum and 558 no, the Danbury (Conn.) News Times reported.
The elementary school has been closed since December when 20 first-grade students and six educators were shot and killed. Students have been attending school at the former Chalk Hill School in Monroe since then, the newspaper said.
"I'm delighted with this overwhelming show of support for Sandy Hook," said Selectman Jim Gaston, "and a major step forward in the healing process and bringing our children home."