Dunbar Grammar School was one of a number of UK schools which received a telephone threat.
The school followed safety procedures and the building went into lockdown as a precaution and was then reopened following a thorough search.
The incident was part of a series of threats to schools and Police Scotland have issued the following statement:
"A number of schools across the central belt have received a threat via the telephone. Police Scotland would like to reassure the public that at present these do not appear to be credible threats, however they are being taken seriously.
"Staff and police are working with local authorities and are currently searching school buildings. Some schools as a precautionary measure, have been evacuated. Significant enquiries are underway."
Police have commended the actions taken by Dunbar Grammar School management following the receipt of the anonymous message.