Staffers arrived at the office, located in the 4100 block of Greenbriar Drive, around 9 a.m. and found the locks pried open, according to a statement from Buzbee's campaign.
They believe it happened when the office was closed between 9 p.m. Wednesday and 9 a.m. on Thursday.
"This is not the kind of news that I want to wake up to in the morning," said Buzbee in the statement. "But it just confirms that my campaign continues to gain momentum and we are on the right track. This will not deter us. We will continue to shine a light brightly on the shadowy side of our local government. We will continue full speed ahead."
It's unclear if any items were taken from the offices.
In February 2019, Buzbee says he pulled a handgun on a burglar who eventually made off with artwork and other valuables worth $21 million from his River Oaks mansion.
READ MORE: Houston mayoral hopeful Tony Buzbee victim of million-dollar heist