The Calgary Board of Education says the password-protected computer was taken earlier this month from an employee's car that was not on their property.
The laptop's hard drive contains a variety of data, including students' names, photos, report card results and comments.
The device also has information on parents' names and phone numbers.
School principals have notified half the parents involved.
The board has also contacted police and Alberta's privacy commissioner. (CHQR)
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