Carmona scored a 29th-minute goal to earn Spain a 1-0 win over England as they secured their first Women's World Cup title.
"The RFEF deeply regrets to announce the death of Olga Carmona's father. The footballer learned the sad news after the World Cup final," the Spanish FA said on social media.
"We send our most sincere embrace to Olga and her family in a moment of deep sorrow. We love you, Olga, you are Spanish soccer history."
An RFEF spokesperson told Reuters that Carmona's father had been fighting a long illness and passed away on Friday.
According to Spanish media outlet Relevo, Carmona's family and friends decided not to tell her so that she could focus on the most important match of her life.
Carmona's mother and brothers travelled to New Zealand during the World Cup's group stage, but then rushed back to Spain. They arrived in Australia on Saturday to support the Real Madrid fullback in the final.