Police have yet to say if the fires are related to each other but suspect arson in the latest blaze.
About 9:30 pm Wednesday, fire alarms sounded in the kitchen as the hallway filled with smoke, the Swedish newspaper Svenska Dagbladet reported. Students evacuated the building but were later allowed to return.
"The kitchen has been cordoned off for forensic examination. We're classifying this as arson," Patrik Linder, with Norrbotten County Police, told Svenska Dagbladet.
Wednesday's incident follow fires on Saturday and Tuesday.