A federal judge granted San Francisco's motion for a preliminary injunction against Oakland.
RELATED: SFO vs. OAK: San Francisco takes Port of Oakland to court over airport renaming
This means the Port of Oakland, which controls the airport, to immediately stop using the name "San Francisco Bay Oakland International Airport."
Court documents show the judge determined San Francisco will suffer irreparable harm from Oakland's name change made back in May in hopes of attracting more business, and that Oakland violated San Francisco's trademark for SFO.
The decision means Oakland cannot use "San Francisco Bay" in any promotions or products either.
RELATED: SF files motion to reverse Oakland airport's name change that it says has caused traveler confusion
The Port of Oakland released a statement to ABC7 News, writing:
"The court's ruling found that two of the three types of confusion alleged by SFO were without merit.
The court order temporarily blocks OAK's new name on the basis of the third type of alleged confusion: that travelers may think OAK is affiliated with SFO. OAK is not associated with SFO, of course, but is rather a convenient and centrally located option for travelers throughout the Bay Area.
We are continuing to review the recent ruling and considering all available options."
This story is developing. Check back for updates.
Read the full injunction below or visit this page.