Sarasadat Khademalsharieh, better known as Sara Khadem, took part in chess championships in Kazakhstan in late December without the headscarf that is mandatory under Iran's strict Islamic dress code, even when representing the country abroad.
Spain's cabinet approved the granting of her citizenship on Tuesday, “taking into account the special circumstances” of her case, the official state journal quoted Justice Minister Pilar Llop as saying.
She was one of several athletes who chose to not to wear the hijab during international championships at a time when Iran was rocked by protests following the death of Mahsa Amini, 22, in morality police custody in September after she was arrested for wearing her headscarf “improperly”.
“With the veil I am not myself,” Ms Khadem told El Pais after moving to Spain. “I don't feel well, and therefore I wanted to put an end to that situation. And I decided not to wear it any more.”
In January, she met Spanish Prime Minister Pedro Sanchez, and played a game of chess with him.
Iran uses “nasty tactics” to put pressure on women competing abroad to wear the hijab, an exiled chess referee told The National in January.
“First they condemn you, then attack you with a cyber army, then put pressure on your family,” said Shohreh Bayrat.
“I never came back to Iran because I think now they (would) just execute me.”
Climber Elnaz Rekabi made headlines in October after competing without a headscarf at an event in Seoul, South Korea.
The BBC said she was forced to make an apology and authorities had threatened to confiscate her family's property over the move.