Al-Nafjan was born in Saudi Arabia, the daughter of a Saudi military officer. She earned a bachelor's degree in English at what at the time was the University of Riyadh. She worked as a school teacher and later a university teaching assistant. She earned a master's degree in Teaching English as a foreign language from the University of Birmingham in the United Kingdom. Al-Nafjan taught pre-medical English at KSU. She encouraged students to discuss their opinions freely and write about them, which a student at the time, Omaima al-Najjar, described as "unheard of in Saudi schools, where we were not allowed to have an opinion or even question the teacher on any matter that involved religion, culture or politics". Al-Nafjan openly stated her strong opinions in favour of women's rights at the time. In 2013, al-Nafjan was conducting research aiming to obtain a PhD in linguistics at KSU.
Blogging and activism
In February 2008, al-Nafjan began blogging as 'Saudiwoman', writing about Saudi social and cultural issues with a focus on women. Her blog became one of the most popular Saudi blogs read internationally. Al-Nafjan blogged about topics that were taboo in Saudi Arabia at the time, including criticising male-guardianship as an "abuse system", opposing child marriage and interventions by the religious police, and documenting internet surveillance by Saudi authorities. On 17 June 2011, she drove a car in Riyadh as part of a women's driving campaign during the 2011 Saudi Arabian protests. She began publishing articles in Western media about the campaign to allow women to drive in Saudi Arabia. In September 2016, al-Nafjan signed a petition as part of the campaign against the Saudi male guardianship system. In October 2013, al-Nafjan was arrested while filming a woman driving. Al-Nafjan was highly active in supporting other activists in the women to drive campaign and in contributing to public debate on the issue.
Detention
Around 15–18 May 2018, al-Nafjan was detained by Saudi authorities, along with Loujain al-Hathloul, Aziza al-Yousef, Aisha al-Mana, Madeha al-Ajroush and two men involved in women's rights campaigning. Human Rights Watch interpreted the purpose of the arrests as frightening "anyone expressing skepticism about the crown prince's rights agenda". Saudi authorities accused the arrested activists of having "suspicious contact with foreign parties", providing financial support to "hostile elements abroad" and recruiting government workers. In November, 2018, she was apparently being held in the Dhahban Central Prison. According to Amnesty International, the detained women's rights activists including al-Nafjan were subjected to torture and abuse. In March 2019, al-Nafjan was released on bail along with some of the other crackdown detainees.