The student is being treated and is expected to recover, health officials said.
School officials are working to identify any students or staff who may have been exposed, and those individuals will be notified. The health department recommends those who are notified to receive a TB skin test at a clinic being planned at the school.
"While the risk of infection is slight, it is important that those who are notified take the time to get tested," said Riverside County Public Health Officer Dr. Cameron Kaiser in a statement.
In October, a student tested positive for tuberculosis at Vista Murrieta High School. More than 200 students and staff were tested at the time, but no other cases were found.
Riverside County health officials say there is no indication the two cases are connected.