Alphabet's (GOOGL) - Get Report Google is being sued by former employees over gender pay discrimination.

Three women former employees filed a class-action lawsuit in San Francisco Superior Court Thursday claiming the tech giant discriminated against women in pay and promotions.

The suit comes just over a month after the company was hit by scandal when an employee wrote a 10-page "manifesto" against Google's diversity initiatives and claimed that women were underrepresented because of inherent psychological differences between men and women.

Thursday suit, which was filed on behalf of all women employed by Google in the last four years, claims that female employees were "systemically" paid lower compensation then male employees performing similar roles.

The plaintiffs also said that Google discriminated against women by "assigning and keeping women in job ladders and levels with lower compensation ceilings and advancement opportunities."

It is also claimed that Google promoted fewer women, or promoted them more slowly. "The net result of this systemic discrimination is that Google pays women less than men for comparable work," the filing said.

The class action also said Google failed to act to rectify the disparity, referring to it a "willful."

The plaintiffs are seeking damages, and want to prevent Google from paying women less for doing substantially similar work than men.

The plaintiffs are Kelly Ellis, Holly Pease and Kelli Wisuri. Ellis claims that she was put on a lower starting salary for her position of frontend software engineer than men in a similar position and that she was denied a promotion despites receiving excellent performance reviews.

Pease claims that Google placed and kept her in the "non-technical" business ladder, with lower compensation and opportunities for upward mobility.

Wisuri also claims that her initial pay was lower than male colleagues.

Google said that it didn't agree with the central allegations of the suit.

The suit follows an investigation by the Labor Department about the salary practices at the company's Mountain View campus.

Alphabet shares closed at $940.13 on Thursday, after falling 1.08%.

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