Kathy Warden will soon run one of the largest defense contractors in the world, a behemoth of a firm that is building the Pentagon’s new stealthy bomber. She has climbed steadily through the ranks at Northrop Grumman, where she now serves as president and chief operating officer, overseeing five of the Falls Church, Va., company’s business divisions. And she is helping to manage the integration of the company’s $7.8 billion acquisition of Orbital ATK.

With her elevation to chief executive of Northrop beginning Jan. 1, Warden will become the latest woman to lead a major defense company. Lockheed Martin, the world’s largest defense contractor, is led by Marillyn Hewson, who has been with the company for more than 35 years. Phebe Novakovic, who served in the Pentagon and the CIA, runs General Dynamics, and Leanne Caret has run Boeing’s defense, space and security division since 2016.

Together, they oversee billions of dollars in revenue and the development of some of the most lethal hardware in the world — and represent a quartet of power unmatched in a town where status is the greatest currency.

“These are people who know their industry really well,” said Kathleen Hicks, a senior vice president at the Center for Strategic and International Studies. “They are technically very competent.”

On Thursday evening, Northrop Grumman announced that Warden would become CEO, replacing Wes Bush, who would step down at the end of the year. “I look forward to leading Northrop Grumman and driving performance for all our stakeholders — working with our employees, our customers, and our shareholders as we move our company forward,” she said in a statement.

Bush said that Warden “has demonstrated exceptional leadership” and that “she brings the vision and values to lead Northrop Grumman into the future.”

While woman have achieved leadership roles at these defense firms, they are still underrepresented in corporate America more broadly. Women hold CEO positions at just 5 percent of the companies in the Standard & Poor’s 500-stock index. They are fighting to rectify pay disparities and overcome workplace harassment at a time when the #MeToo movement has a foothold in American society.

But Loren Thompson, a defense consultant, said he believes that in the defense and aerospace industries, things are beginning to change.

“Twenty years ago, when I would go to meetings of the Aerospace Industries Association, it seemed like everyone in the audience was a middle-age white male,” he said. “To see most of the biggest defense and aerospace companies in America run by women seems like a real cultural transformation.”

A study by Aviation Week found that women made up 24 percent of the workforce in the aerospace and defense industry last year, up from 22 percent in 2016. Nearly a quarter of executive-level positions were held by women last year, the study found.

While that’s an improvement, “25 percent is not 50 percent,” Hicks said.

Many defense companies still have an “old-fashioned culture,” she said, with “a lack of diversity of thought, and sexism can be a piece of that.”

There is frustration among many women that they are often “the only woman in the room, or being looked at as a note-taker,” she said.

Caret, who leads a $21 billion business at Boeing, joined the company in 1988 and remembers when, in dealing with the Pentagon, “there weren’t many women at the table.”

“Over time we saw more and more women in uniform on the customer’s side of that table,” she said. “I think that helped motivate the companies to do the same.”

While she said she wanted to be viewed as a leader first and foremost, she said in an email: “At the end of the day I want to be known as a good leader, not only as a good female leader. My goal is to be a role model for men as well as women.”

But she said that “every woman leader today benefits from the efforts of so many people who came before us. Our responsibility is to open more doors for the women who will come after us.”

Under Hewson, Lockheed Martin has seen tremendous growth. The Bethesda, Md.-based company makes the F-35 Joint Strike Fighter, the most expensive weapons system in the history of the Pentagon. Last year, it had $51 billion in revenue. The company employs 100,000 people across the globe. Since Hewson became CEO in 2013, the stock price has more than tripled.

In a post in LinkedIn, she wrote that “I want to ensure that women at Lockheed Martin have the same opportunities to grow and succeed as I did.” She said that companies need to “beware of hidden biases. Mad Men-style sexism may be behind us, but subtler and even subconscious forms of bias still disadvantage women.”

Hewson was tapped for the job after a male colleague in line for the position had an improper relationship with a subordinate. When she asked whether she would take the position, Hewson reportedly said, “I’m ready.”

Correction: An earlier version of this report said Warden leads three Northrop business divisions. She leads five.