The state Senate unanimously passed the bill, which would make it a misdemeanour to surreptitiously take photos up women's dresses without their consent. A teachers union proposed the measure after a student took so-called upskirt cellphone photos of an educator and shared them online.
The Senate vote came three months after an Oregon judge ruled a 61-year-old man did nothing illegal when he snapped photos up a teen's skirt in a Target store.
"You've probably seen in the news reports that currently the tactic of what's known as upskirting is not covered for various reasons," said Sen. Floyd Prozanksi, a Eugene Democrat. "This bill will, in fact, cover the infractions, the conduct and hold people accountable for that."
The judge in the Target case said that while the act was lewd and appalling, it didn't violate the state's existing voyeurism laws because the girl was clothed and in a public place.
Laurie Wimmer, an Oregon Education Association lobbyist, has said her organization proposed the bill in response to an incident a year ago involving teacher Dana Lovejoy.
In February, Lovejoy testified in favour of the measure before a House committee. She wore the same long, black dress she had on when the incident happened.
Lovejoy told lawmakers that during one of her classes last May, a middle school student stuck a camera phone under her skirt as she leaned over to help other students.
The student who took the images then disseminated them to classmates over various social media networks.
"Upon learning what happened I felt immediately in shock and violated. Not only was I photographed without my consent, not only was it of my genital area, but the majority of the school had seen it before I was even aware it existed," Lovejoy told the House Committee on Judiciary.
"Our laws have not kept up with technology," she added.
Several other states — including Kentucky, Florida, Massachusetts and Pennsylvania — have passed measures outlawing clandestine upskirt photos, though a similar bill in Wisconsin has stalled in the Senate.
The Massachusetts legislation also was aimed at closing a gap in privacy laws. It was passed two days after the state's highest court ruled a man who took cellphone photos up the skirts of female subway passengers in Boston was not violating state laws as written.
The Oregon proposal heads back to the House for consensus.