EVERETT — City residents sent an emphatic message Saturday: They want Wynn.

By a landslide vote of 5,320 to 833 — 86.5 percent to 13.5 percent — Everett voters endorsed a $1.2 billion gambling resort proposal from Las Vegas developer Steve Wynn, who wants to build on vacant industrial land on the Mystic River waterfront.

The vote was the first binding referendum under the 2011 state law that legalized casino gambling in Massachusetts. No project can compete for a coveted casino license unless the voters of the host community approve the proposal at the ballot box.

About 32 percent of the city’s 19,400 voters turned out for the unusual Saturday referendum, according to the city clerk’s office.

“The voters of Everett have spoken clearly and decisively,” Wynn said in a statement. “The vote heightens our enthusiasm and dedication to this fine project. We thank the voters of Everett for their support and for making all of our efforts so easy.”

Casino opponent Evmorphia Stratis said she was not surprised by the results, given that the pro-casino group “Everett United, a supposedly a grass roots organization, had so much money pumped into it by Steve Wynn that they overwhelmed Everett with their campaign.”

She said she will continue to oppose the project at the state gambling commission, and more broadly through a referendum effort to repeal the state’s casino law.

Voters interviewed Saturday outside the Edward G. Connolly Center, one of the city’s polling stations, were overwhelmingly in favor of the referendum, saying the economic benefits of the project would outweigh potential headaches.

“It’s a wasteland down there; there hasn’t been any development,” said Dana Ringdahl, a 51-year-old lifelong resident of Everett, speaking of the former Monsanto chemical site where Wynn has proposed placing his project. “Maybe we can get beyond the image of being an industrial city and become a more happening place.”

Ringdahl said a casino could make the city a destination. “We have good access to Boston and to transportation,” Ringdahl said. “We’re near the airport. Maybe it will be another stop on a tourist trip.”

Opponents argued that a casino would bring limited benefits, or even new challenges, to a city with more pressing problems.

“Anything is more important,” said Gina Forte, 21, who thinks Everett’s schools and congested roads need urgent attention.

“A casino is not what I’d want to be known for,” she said. “One of the things we’re known for is football, which is good, because it’s a school thing. . . . [A casino] might be cool at the beginning, but ultimately I think it will be a waste.”

Other “no” voters, who acknowledged they were likely a minority, said Everett should focus on cleaning up the city and reducing crime.

The state’s expanded gambling law authorized up to three resort-style casinos, no more than one in each of three regions of the state, as well as a slot parlor that can be built anywhere. Wynn is one of three applicants for the Greater Boston license. The others are Suffolk Downs, the thoroughbred racetrack that straddles the East Boston-Revere city line, and Foxwoods, which has proposed a casino about 35 miles from Boston in suburban Milford.

Votes have not yet been scheduled for the other projects.

Wynn has promised to build a five-star hotel with 551 rooms in a bronze glass tower in Everett. Project plans also include an 18,000-square-foot ballroom and a 100,000-square-foot casino, in addition to a spa, nightclub, restaurants, shops, and an indoor glass “winter garden.”

A Wynn casino supporter, Richard “Dickie” Cannatelli, has lived in Everett for all of his 72 years, and said he remembers the city’s industrial glory days in the 1940s. He is hoping a casino will return luster — and revenue — to Everett.

“We have 35 acres of land. What else are we going to do with it?” he said. “That property has been a topic of debate ever since Monsanto left. Let’s clean it up and put something there for the people of Massachusetts.”

While some residents are concerned that a casino could snarl traffic, Cannatelli reasoned that a casino in a neighboring community would also cause traffic in Everett.

“The traffic in the city can’t be any worse than it is,” he said.

Wynn has designed some of the most elaborate casinos on the Las Vegas Strip, including the Mirage, Bellagio, Treasure Island, and the Wynn and Encore resorts.

Sal Sachetta, the 82-year-old president of the Board of Aldermen, said he supports the casino and was confident the referendum would pass.

“Our school department has a high influx of pupils, and they could really use the money” a casino would bring, he said. “That property is contaminated. No one will ever use it or want to clean it up.”

The Suffolk Downs proposal in East Boston had most worried Sachetta, who felt the competing project might enjoy more political support with prominent figures such as Boston Mayor Thomas M. Menino backing it. But lately, he senses that Wynn’s proposal has the most momentum of the three casinos competing for the area’s one license.

“My doubts about our chances have been diminished,” he said.

The state gambling commission, which controls casino licenses, is expected to award the Greater Boston license in early 2014.