Spain imposes national night
Prime Minister Pedro Sánchez said the curfew, between the hours of 23:00 and 06:00, would come into force on Sunday.
Under the emergency measures, local authorities can also ban travel between regions, he said.
Mr Sánchez said he would ask parliament to approve an extension of the new rules from 15 days to six months.
Spain was hit hard during the first wave of the pandemic earlier this year and imposed a much more restrictive lockdown - one of the toughest in the world.
Like many other European regions, however, it has been hit by a second wave of infections.