Tawakul Karman, a Yemeni journalist and activist, is one of three women awarded the 2011 Nobel Peace Prize. She becomes the first Arab woman to win the prize.
The 32-year-old mother of three founded Women Journalists Without Chains in 2005.
She has been a prominent activist and advocate of human rights and freedom of expression for the last five years, and led regular protests and sit-ins calling for the release of political prisoners.
The Norwegian Nobel Committee cited Ms Karman and the two other winners for their "non-violent struggle for the safety of women and for women's rights to full participation in peace-building work".
The Nobel jury specifically lauded Ms Karman for playing, "in the most trying circumstances, both before and during the Arab Spring... a leading part in the struggle for women's rights and for democracy and peace in Yemen."
Ms Karman told the BBC Arabic Service: "I'm so happy with the news of this prize and I dedicate it to all the martyrs and wounded of the Arab Spring… in Tunisia, Egypt, Yemen, Libya and Syria and to all the free people who are fighting for their rights and freedoms.
"Actually I didn't know I was nominated for the Nobel Peace Prize until now. I only knew about it through BBC Arabic and al-Jazeera, so thank you very much."
In comments to the AFP news agency she said that the prize was "a recognition by the international community of the Yemeni revolution and its inevitable victory".
Ms Karman has led rallies in the continuing protests against the rule of President Ali-Abdullah Saleh.
Speaking to the BBC in April 2011 in Change Square in Sanaa, the heart of the popular demonstrations against Mr Saleh, Ms Karman said she was astonished at the protests: "I could never imagine this. In Yemen, women are not allowed out of the house after 7pm, now they are sleeping here. This goes beyond the wildest dream I have ever dreamt, I am so proud of our women."
She is a member of Yemen's leading Islamist opposition party, the Islah - a conservative, religious movement that calls for reform in accordance with Islamic principles.
She has campaigned to raise the minimum age at which women can marry in Yemen.
She has been jailed several times for her activism, pilloried in the official media and attacked. Unusually for a woman in Yemen, Ms Kamran wears a headscarf not a full face veil.