The latest victim is a woman who was injured in the coastal town of Cambrils.
She was among a crowd of people hit by a car overnight.
Police there shot and killed five men wearing fake bomb vests.
The attack came just hours after a van ploughed through tourists at Las Ramblas in Barcelona.
The Department of Foreign Affairs has updated travel advice for those heading to Spain.
They say Irish people should increase their security awareness and exercise more caution in tourist areas.
They say those in Spain should follow the instructions of local law enforcement, but have not increased their security status rating for the country.
