The engineers on Tuesday accepted the aerospace company's four-year contract offer while technical workers rejected it and authorized a future strike.
Bill Dugovich of the Society of Professional Engineering Employees in Aerospace said the votes mean the new contract for the 15,550 engineers is in place.
He said negotiators hope to resume contract talks soon on behalf of the 7,400 technical workers.
"If Boeing doesn't act in good faith and the techs do go on strike, you'll have people who are involved in the supply chain and the logistics and a lot of the actual manufacturing of aircraft. So they're key people. Boeing can not build aircraft without them," said Ray Goforth, SPEEA's executive director.
Boeing Commercial Airplanes President and CEO Ray Conner said in a statement that the company was pleased with the engineers' vote but "deeply disappointed" in the technical workers' rejection of what he called the company's "best and final" offer.
While a strike by the technical workers is not imminent, Dugovich said the vote meant the negotiating team can now call one at any time. Engineers and technical workers work on plans for planes and solve problems that arise on the factory floor.
SPEEA last went on strike for 40 days in 2000.