Salma bint Hizab al-Oteibi won a seat on the council in Madrakah in Mecca province. She was running against seven men and two women in Saturday's vote, BBC online reports Sunday.
Women have also won in several other regions in the country, including Jeddah and Qatif, reports suggest.
Saudi women still face many curbs in public life, including driving.
A total of 978 women registered as candidates, alongside 5,938 men, but female candidates were not allowed to address male voters directly during campaigning.
Elections of any kind are rare in the Saudi kingdom – Saturday was only the third time in history that Saudis had gone to the polls.
There were no elections in the 40 years between 1965 and 2005.
There were 2,100 council seats available. An additional 1,050 seats are appointed with approval from the king, BBC notes.
