The goal is to crack down on groups of rowdy teens.
Guests under 18 years old must be with a parent or guardian starting at 5 p.m. Monday through Saturday, and starting at 3 p.m. on Sunday.
Minors working in the mall must show proof of work status.
The new policy begins Tuesday and will be in effect throughout the entire mall, including parking lots and garages.
Some consumers welcome the change.
"It would be like, 'Oh I'm back in high school again.' I'm surrounded by all these teenagers around, running around everywhere. Running amuck," said Montgomery County resident Maureen Feeney.
Abington police helped advise the mall on which times they've seen an uptick in shoplifting, fights or nuisance issues.
The policy will be enforced by mall security who will check IDs at the door and escort those who are not of age out.
"I'm in the middle. I understand, but maybe let them have some freedom. Not all kids are the same. I'm a school counselor, so kids are different. They should be able to make choices," said Olivia Simmons of Mount Airy.
The policy mirrors those enacted at the Cherry Hill Mall in New Jersey and the Fashion District in Center City Philadelphia.
Though malls are struggling, shoppers say this could actually boost business.
"I don't think those kids are buying anything anyway, I think they are just hanging out. I think it might help the industry if people know someone is policing whether or not kids are coming in and acting up," said Megan Schmidt of Lafayette Hill.
Both the Willow Grove Park Mall and Abington police say this is a proactive measure. There hasn't been a massive incident, but they don't want one to happen.