At a media conference in Paris where she is on a private visit, Ebadi called for all political prisoners in Iran to be released.
"I call on the Iranian government to respect human rights and I hope in the future things will move positively ... What is most urgent is respect for freedom of expression and the release of prisoners of conscience," she said.
Ebadi, 56, was given the prize "for her efforts for democracy and human rights," particularly for women and children in her country, which has been under Islamic rule since a 1979 revolution, the Nobel Committee said.
Immediately after the news, Edabi said she was "shocked" at the unexpected honour but believed the prize - which carries a 10 million Swedish crowns ($1.32 million) purse - "will be important for my work for human rights and for citizens in Iran."
In a pointed gesture, she appeared without the Muslim headscarf Iran demands its women wear in public everywhere, even outside the country.
She won from a record field of 165 candidates including Pope John Paul II and former Czech President Vaclav Havel.
"She sees no contradiction between Islam and fundamental human rights," the head of the committee Ole Danbold Mjoes said in the prize citations.
"The legal keys that Shia religion has given us enable us to
transform and act according to the times," Ebadi wrote in a recent article.
10 other women have won the award:
1997 - Jody Williams, coordinator of the International Campaign to Ban Landmines
1992 - Rigoberta Menchu, Guatemalan human rights leader
1991 - Aung San Suu Kyi, Detained Burmese opposition leader
1982 - Alva Myrdal
Sweden's minister for disarmament
1979 - Mother Teresa of Calcutta
1976 - Betty Williams and Mairead Corrigan, co-leaders of the "Community of Peace People", a movement to end sectarian violence in Northern Ireland
1946 - Emily Greene Balch, US pacifist and honorary international President of the Women's International League for Peace and Freedom.
1931 - Jane Addams, US philanthropist who organised social work among the poor in Chicago and was international President of the Women's International League for Peace and Freedom
1905 - Bertha Sophie Felicita von Suttner, Austrian baroness who wrote an anti-war book, "Lay down your Arms", and was honorary president of the Permanent International Peace Bureau
The prize will be handed over at an official ceremony in Oslo on 10 December.
Ebadi won a separate human rights prize in Norway in 2001, the Rafto Prize.
"In my country, Iran, there is still a continued struggle for democracy and human rights," she wrote this year.
"Iranian people want to reform their political and legal system," she said. "They are protesting against the few people who have power."
Nobel watchers say that the five-member committee, which comprises three women, probably chose Ebadi as a way of promoting change, rather than rewarding the ailing pope or to
Havel for a lifetime of peace work.
Analysts say the committee has sought to promote moderates in the Muslim world since the 11 September 2001 attacks on the US.
After some delay, the Iranian government said it was pleased by the news, but the country's hardline conservatives saw the award as a Western attack on their mode of Islamic rule.
A conservative Iranian leader, Assad Allah Badamshian, chief of the Islamic Coalition Association, called the honour a "disgrace" and claimed that Iran's arch-foe, the United States, had a hand in giving the prize to a "so-called reformist".
The Nobel decision has upset others too. Former Polish president and Nobel laureate Lech Walesa said the Norwegian Nobel Committee made a "big mistake" in awarding the 2003 peace prize to the Iranian jurist rather than Pope John Paul II.
But by winning the Nobel award, Ebadi joins a select group of women. She is only the 11th woman to win the Nobel Peace Prize since it was set up in 1901.