Laura Berlinsky-Schine

Think technology is a boy's club? While there's still a gender gap in Silicon Valley, women are gaining ground in STEM fields and tech companies across the world. But that's actually nothing new. As you'll see from the below list, despite many people's assumptions that there aren't many prominent women in tech, female STEM professionals have been revolutionizing STEM fields and the technology industry for as long as men have.

Here are seven powerful women—some living, some deceased—who have changed or are still changing the tech industry for the better.

1. Sheryl Sandberg

According to Forbes, the Facebook chief operating officer has a net value of $1.53 billion. The second in command at the world's reigning social network is also the founder of, a nonprofit organization that empowers women, and the author of Lean In and Option B.

2. Susan Wojcicki

The CEO of YouTube served as Google's first marketing manager and climbed the ladder to senior vice president of Advertising and Commerce. It was Wojcicki's idea to acquire YouTube, and she oversaw the $1.65 billion purchase of the video platform in 2006. In 2014, she became YouTube's chief executive officer.

3. Williamina Fleming

Not a name you recognize? Born in 1857, Fleming emigrated from to the United States with her husband, who later left her. She became a maid in the household of Edward Pickering, a professor of astronomy at Harvard and the director of the Harvard College Observatory. Pickering then hired Fleming to do clerical work and mathematical calculations at the Observatory, where she developed a new classification system later known as the Pickering-Fleming System. In 1906, she became the first female member of the Royal Astronomical Society Her achievements include discovering the existance of white dwarfs, 10 novae, 52 nebulae, and 310 variable stars.

4. Meg Whitman

Now CEO of Jeffrey Katzenberg's mobile media startup, NewTV, Whitman served as president and CEO of eBay from 1998 to 2008, overseeing its expansion from 30 employees to 15,000 employees. Under her leadership, the company also expanded from $4 million in annual revenue to $8 billion.

Whitman later served as CEO of Hewlett-Packard, overseeing the division of the company into HP Inc. and Hewlett Packard Enterprise.

5. Ginni Rometty

The first woman to head the company, Rometty is the CEO of IBM. She joined the company as a systems engineer in 1981. As chair, Rommetty has concentrated on developing and honing cloud and cognitive computing systems, including supercomputer Watson.

6. Grace Hopper

The "mother of computer programming" held a Ph.D. in mathematics from Yale and joined the U.S. Navy during World War II. She was assigned to program the Mark I computer, one of the first electromechanical computers used for war efforts, at Harvard. After the war, Hopper continued to work in computing and led the team that invented the first computer language compiler, which led to the creation of the COBOL language. All subsequent computer programming languages are based on Hopper's work.

7. Annie Easley

In 1955, Easley read a story about twin sisters who worked for the National Advisory Committee for Aeronautics (NACA) as "human computers" in a local newspaper. The next day, she applied for a job at NACA, where she was hired to perform complex mathematical calculations.

As technology replaced humans, Easley became a skilled programmer. She is responsible for developing and implementing code used in researching energy-conversion systems, including the technology that would eventually power hybrid cars. She also laid the groundwork for launching future satellites and space vehicles.

During her career, Easley also helped managers address issues such as gender, race, and age discrimination.