Seven cases from Saugeen-Maitland Hall have been confirmed along with four cases from Ontario Hall.
Another outbreak at a Western University residence, Essex Hall, remains active. It was declared March 2 and involves at least seven cases.
In a statement from Western University Friday, the school said all students living in Saugeen-Maitland Hall and Ontario Hall are being notified.
Those who have tested positive and some close contacts have been moved to a quarantine location outside of the residences.
Western says contact tracing is led by the MLHU and they will notify anyone considered a close contact.
Floor lounges and study rooms in both residences have been closed. On-site testing to students on affected floors is also being provided.