Well, sure. We wouldn't want her making any life-changing decisions until she comes of age.
The youngster was married off by her father in exchange for a £4,000 dowry.
Relatives of the girl said the groom had agreed not to consummate the marriage for 10 years and to allow the youngster to live with her mother.
The girl's mother, who is separated from her husband, had filed a petition for divorce with a court in Unayzah, 135 miles north of Riyadh.
But the court ruled that the girl must file the case herself when she reaches puberty, it was reported.
"The judge has dismissed the plea because she does not have the right to file such a case, and ordered that the plea should be filed by the girl herself when she reaches puberty," lawyer Abdullah Jtili told the AFP news agency.
The marriage contract was signed by the father and the groom.
It is understood the father had debt problems and wanted to secure an advance dowry.
Arranged marriages involving pre-adolescents are occasionally reported in the Arabian Peninsula, including in Saudi Arabia where the strict conservative Wahabi version of Sunni Islam holds sway and polygamy is common.
A girl aged eight was granted a divorce in Yemen in April after her unemployed father forced her to marry a man of 28.