The FDA decision came days before a court-imposed deadline.
Tuesday, the FDA lowered to 15 the age at which females can buy the emergency contraceptive without a prescription, and said it no longer has to be kept behind pharmacy counters.
Now the pill can be sold on drugstore shelves just like condoms.
Buyers would have to prove their age at the cash register.
Earlier this month, a federal judge had ruled there should be no age restrictions and gave the FDA 30 days to act. The FDA said its latest decision was independent of the court case.
The Associated Press contributed to this report.