Orlando's police chief said she has been charged with aiding and abetting by providing material support to a terrorist organization and obstruction of justice.
Early in the investigation, law enforcement said they were considering pursuing criminal charges against her if they could prove she knew about the attack and did nothing to stop it.
As of early Monday afternoon, other details were still unknown. But Attorney General Loretta Lynch did confirm the arrest was made.
Lynch told MSNBC, "This is a matter that we continue to take very seriously. It was always our goal. We said from the beginning we were going to look at every aspect of this case, of every aspect of this shooter's life."
The gunman's wife is scheduled to make an initial appearance in federal court Tuesday.