The three prizewinners share the 2011 award "for their non-violent struggle for the safety of women and for women's rights to full participation in peace-building work," Norwegian Nobel Committee president Thorbjoern Jagland said in his announcement.
"We cannot achieve democracy and lasting peace in the world unless women obtain the same opportunities as men to influence developments at all levels of society," he added.
Sirleaf, 72, made history when she became Africa's first elected woman president in 2005. She took power in a nation traumatised by 14 years of brutal civil war that left 250,000 dead and economic devastation, with no electricity, running water or infrastructure.
The Nobel Committee said that "since her inauguration in 2006, she has contributed to securing peace in Liberia, to promoting economic and social development, and to strengthening the position of women."
Sirleaf's rise to power might not have been possible without the efforts of Gbowee, 39, an activist who led Liberia's women to defy feared warlords.
She pushed men toward peace by inspiring a large group of both Christian and Muslim women to wage a sex strike during what was one of Africa's bloodiest wars.
The Nobel Committee hailed Gbowee for having "organised women across ethnic and religious dividing lines to bring an end to the long war in Liberia, and to ensure women's participation in elections."
Tawakkul Karman is a 32-year-old Yemeni activist and journalist who has braved several stints in prison in her struggle for women's rights, press freedom and the release of political prisoners in Yemen.
She is the first Arab woman to the win the Peace Prize.
The Nobel jury hailed her for "in the most trying circumstances, both before and during the 'Arab Spring'… (playing) a leading part in the struggle for women's rights and for democracy and peace in Yemen."
