Administrators at Savanna High School, at 301 N. Gilbert St., contacted the Anaheim Police Department Thursday morning after learning about threats that had been posted online, police said in a news release.
Police worked with school personnel to identify the students allegedly behind the plan.
The unidentified students were found and arrested before classes began. They were being held on suspicion of making criminal threats and were set to be booked at Orange County Juvenile Hall.
No information about the students was provided by police.
Graduation was held for Savanna High seniors on Thursday, which marked the end of the semester, according to the school calendar.
The school is part of Anaheim Union High School District.