The United States men's national team wore orange wristbands to show their support for a letter the U.S. Soccer Federation sent to Congress.
The mass murder of 19 school children and two teachers in Uvalde, Texas, was the subject of a letter. 10 days later, another teenager shot and killed 10 people at a supermarket in Buffalo, New York.
Gun control legislation is expected to be voted on by the House.
"With legislation being considered in the coming days in the House and Senate, we urge you to stand with the majority of Americans who support stronger gun laws," the letter said.
Senior national teams have worked with the USSF to amplify social justice messaging. The men's national team adopted the "Be The Change" slogan and wore warm up gear in support of the Black Lives Matter movement.
In the past, the USWNT wore "Black Lives Matter" on its warm-ups. Several USWNT players wore athletic tape on their wrists with the words "Protect Trans Kids" written on it.
In March, the USSF board of directors passed a preliminary resolution banning discrimination at USSF-hosted events. The resolution will be forwarded to the rules committee to make sure it doesn't conflict with other policies.
Some people think athletes shouldn't get involved in political issues. The safety of the children in our country is a sacred responsibility that we all share.
It would be irresponsible to not use our platform to call for change. Many of you refuse to take action, that's why we're talking about it.