Lockheed Martin Corp said about 3,000 employees would be furloughed on Monday due to the US shutdown.
The company said the number of employees was expected to increase every week if the shutdown continued.
Lockheed said the furloughed employees include those who work at government facilities that have closed and those whose work requires a government inspection that cannot be completed.
A political standoff over the US budget has shut down non-essential government services and hurt companies that rely on federal employees and funding.
"I'm disappointed that we must take these actions and we continue to encourage our lawmakers to come together to pass a funding bill that will end this shutdown," Lockheed Chief Executive Marillyn Hewson said.