It alleges gender-based discrimination by the U.S. Soccer Federation.
The US women, who finished second to England in the just-concluded SheBelieves Cup tournament at American venues, are set to defend their crown June 7-July 7 at the Women's World Cup in France. Despite this, the latter get paid way more, and as a result, the women's squad has fought for equal pay for years.
They are requesting back pay, damages and other relief for any current or former team member dating back to February 5, 2015.
"Each of us is extremely proud to wear the United States jersey, and we also take seriously the responsibility that comes with that", Morgan said in a statement reported by The Associated Press.
The players also want the USSF to "promote gender equality".
The suit states that the women filed on behalf of themselves and all other similarly situated current and former women's national team players "who the USSF has subjected to its continuing policies and practices of gender discrimination".
The USSF did not have an immediate comment.
Serena Williams and other prominent past and present American tennis players have expressed their support for a lawsuit filed by the United States women's national soccer team against their federation alleging gender discrimination in wages and conditions.
The lawsuit points out that for their success in winning the 2015 Women's World Cup, the US women were paid less than a third of what the USA men were paid for losing in the Round of 16.
Now begins this new path of legal action, and we'll have to see what comes out of it. When members of the women's team first approached U.S. Soccer in 2012 about receiving the same pay scale, they said the organization's response was to offer the compensation only when the women played teams ranked in the top 10 worldwide, and only if they won the match.
US midfielder Julie Ertz stands on the pitch after the team's 2-2 draw against England in a SheBelieves Cup women's soccer match Saturday, March 2, 2019, in Nashville, Tenn. We believe that there has been discrimination against us, " Rapinoe said. "We are capable of doing that, so why wouldn't you invest in a team that's capable of capturing so many hearts around America?"
No 13 Carli Lloyd celebrates a goal during the 2015 Women's World Cup in Vancouver.
"I think at some point, in every sport, you have to have those pioneers and maybe it's time for soccer", she said.
"It puts a face and a name to each one of these claims of discrimination", she said.
After negotiating contracts, the women settled on a four-year agreement in 2017. They received raises in base pay, bonuses and better provisions for travel and accommodations. It also gave the players some control of certain licensing and marketing rights.
The lawsuit filed Friday seeks "an adjustment of the wage rates and benefits" for the women.
"This lawsuit is an effort by the plaintiffs to address those serious issues through the exercise of their individual rights".