They marched outside the Illinois National Guard Northwest Armory on Chicago's west side Saturday morning.
The group, called Our Sisters Keepers is hoping to raise awareness about sexual harassment in the military.
"Military sexual assault is a thing, and we need to let our soldiers know that we are there for them," said military veteran Eli Morales.
They are calling for civilian oversight of complaint investigations. The groups also wants to prevent sexual predators from ever entering the military,
"Because that's not a thing right now," said Air Force Veteran Estafania Gibson. "Sexual predators can enter the military."
The group stood in solidarity with the Guillen family as well as their effort to change legislation.
The "I am Vannesa Guillen Bill" which was proposed on July 30, will allow soldiers to report a sexual assault incident to a third party.
RELATED: 'I will help': Pres. Trump pledges to pay for Vanessa Guillen's funeral
"This bill can save lives, it can save someone like Vanessa," said Morales. "We are trying to serve a country and we demand to be treated with respect."