8:37 AM PT -- Team owner Dan Snyder has finally weighed in on the allegations ... saying the alleged behavior has "no place in our franchise or society."
"This story has strengthened my commitment to setting a new culture and standard for our team, a process that began with the hiring of Coach Rivera earlier this year," Snyder added.
Dan says once the law firm he hired to investigate the claims completes its probe, "we will institute new policies and procedures and strengthen our human resources infrastructure to not only avoid these issues in the future but most importantly create a team culture that is respectful and inclusive of all."
"My daughter works for the team and I sure as hell am not going to allow any of this!"
That's Washington head coach Ron Rivera promising to shut down ANY toxicity in his new org ... this after 15 women came out and said they experienced rampant sexual harassment and verbal abuse during their time with the team.
The women -- per a Washington Post report -- claimed high-ranking execs made inappropriate comments to them, and on at least one occasion, called a woman "f**king stupid."
In fact, some of the ex-female employees say it got so bad ... they would meet up in the bathroom on lunch breaks and cry over their experiences.
58-year-old Rivera -- who just took over the reins as the team's head coach this offseason -- released a statement to ESPN Thursday night ... vowing to change the culture.
"Biggest thing is we have to move forward from this," Rivera said, "and make sure everybody understands we have policies that we will follow and that we have an open door policy with no retribution."
For the team's part ... it has already parted ways with several of the employees accused of wrongdoing in the WaPo report -- and says it's hired an attorney to investigate further.
The NFL, meanwhile, said in a statement early Friday morning it takes the claims very seriously and will work with Washington's investigators to determine the necessary steps going forward.
"These matters as reported are serious, disturbing and contrary to the NFL's values," the league said. "Everyone in the NFL has the right to work in an environment free from any and all forms of harassment. Washington has engaged outside counsel to conduct a thorough investigation into these allegations."
"The club has pledged that it will give its full cooperation to the investigator and we expect the club and all employees to do so."
The statement continued, "We will meet with the attorneys upon the conclusion of their investigation and take any action based on the findings."