Spanish government officials said they will extend benefits for large families until their youngest children turn 26.
The current age limit is 21 for the oldest child, but government officials said chronic unemployment in Spain meant older children had to remain at home, which cost the entire family its benefits.
Health Minister Ana Mato said the change would "ensure equality for all children in the family."
Think Spain said 87 percent of Spanish families have three children or more, and more than half of Spaniards 26 years of younger were either attending college or looking for work.
Unemployment in Spain this summer topped 27 percent, government figures indicated.