Police said Friday that the two face charges of harassment, interference with faculty and students at an educational institution, and conspiracy. They were booked and released to their parents.
Boulder Valley schools says the threat was posted last weekend to the Boulder High School senior Facebook page.
The school brought in more Boulder police officers on Monday, as the threats were specific to that day.
The names of the two juveniles weren't disclosed.
(Copyright 2012 by The Associated Press. All Rights Reserved.)