As votes rolled in Tuesday, 66 percent of state locals voted in favor and 33 percent voted against Referendum 120, which mandates that doctors notify a parent or legal guardian at least 48 hours beforehand.
Notice will not be required, however, if there is a medical emergency, if it is waived by a youth in court in a sealed proceeding, or if it is waived by the parent or guardian.
Physicians who perform an abortion in violation of this act, or who coerces a minor to have an abortion, will now be subject to criminal prosecution and civil liability.
Michael Pauley, the campaign consultant for the successful parental notification law in Alaska in 2010, helped with Montana's campaign and had predicted victory for the legislation.
But in Florida, locals rejected a law Tuesday that would have exempted taxpayers' money going to abortion except in rape, incest or life endangerment.
State unofficial results say 55.22 percent voted against and only 44.78 percent voted in favor of passing Amendment 6, which would have required that minors have parental consent to have an abortion.
A Florida ballot amendment requiring parental notification, not consent, became law after it passed 65 percent to 35 percent in 2004.
The proposed amendment would have superseded statutory limitations by putting a prohibition in Florida's Constitution.
The law would have also limited the right to privacy relating to abortions and any court rulings that had upheld that right.