Police were on hand at the start of the school day at Wyomissing High School on Wednesday.
Police were there because of a threat that was found written in a girls' bathroom, according to a notice on the district's website.
Students were searched as a precaution.
Tulpehocken Junior-Senior High School was locked down on Tuesday after a threatening message was found on a bathroom wall.
A 12-year-old student has been charged with terroristic threats and disorderly conduct in juvenile court.