The elegant ceremony, held in Oslo's City Hall, marked the first time an African woman has won the prestigious award. It is also the first time the peace prize has gone to an environmentalist -- a sign that ecological issues could be gaining political prominence.
Maathai was selected by the Nobel Committee for her campaign to save Africa's forests.
The 64-year-old biologist is the founder of the Green Belt Movement, a campaign that has resulted in the planting of more than 30 million trees across the continent.
Maathai, who also serves as Kenya's deputy environment minister, used her acceptance speech to call on Africans to lead the fight for change in their own countries.
"My fellow Africans, as we embrace this recognition, let us use it to intensify our commitment to our people," Maathai said. "To reduce conflicts and poverty and thereby improve the quality of life of our people. Let us embrace democratic governance, protect human rights, and protect our environment. I am confident that we shall rise to the occasion. I have always believed that solutions to most of our problems will have to come from us."
Maathai -- a tenacious, outspoken activist who has clashed repeatedly with government officials over the course of her environmental career -- also spoke of the need for women to play a greater role in political decision-making.
Speaking to reporters on the eve of her award ceremony, she said women can make a valuable contribution to the fight for world peace, but must first be given the political authority to make their voices heard.
The Nobel Committee's October announcement naming Maathai as this year's peace laureate was met with jubilation in much of Africa -- particularly in Kenya, where massive deforestation has resulted in drought and poverty affecting millions of people.
Konchora Guracha, an environmental reporter with the Kenyan newspaper "The East African Standard," said Maathai's achievement will make a big difference in the way many Kenyans view ecological issues.
"It's almost an awakening call for this country, because I think with her winning of the Nobel Peace Prize, [Maathai] has risen from basically a local eco-activist to an international icon, so to speak," Guracha said. "So that kind of celebrity that she's got now will likely put her on a different pedestal, a different platform. That will definitely go a long way toward changing the way we look at the environment."
Maathai's award comes amid controversy over her reported statement that HIV/AIDS -- which has ravaged Africa over the past two decades -- is the result of a botched laboratory experiment.
News media in Africa -- including the "Standard" -- also have reported that Maathai has claimed HIV/AIDS was deliberately created by Western scientists to decimate the African population.
Maathai denied making such allegations.
In a statement issued by the Nobel Committee, she stated that she does not believe the virus was developed by white people to destroy Africans. Such views, she wrote, "are wicked and destructive."
She also expressed hope that scientists will find conclusive evidence about the source of AIDS in order to dispel the belief that the disease was the result of a laboratory accident.
The "Standard" has stood by its reports. Guracha said many Kenyans were surprised to hear such statements from a scholar of Maathai's standing. But he said most people know enough about HIV/AIDS to disregard her comments.
"Information is so much out in the public domain -- even in Kenya these days -- about HIV/AIDS. There's so much information on AIDS and what AIDS is all about -- that it's universal, that it's mankind, that it affects everybody -- the rich, the poor, the green, the yellow, the red," Guracha said. "I wouldn't imagine it's going to change the public thinking that AIDS was actually cultured in some Western laboratory to come and decimate the black population. I don't think so."
Nobel prizes for medicine, physics, chemistry, literature, and economics were also awarded today in a twin ceremony in the Swedish capital, Stockholm.
Nobel Peace Prize winners of the recent past include the United Nations and its Secretary-General Kofi Annan, former U.S. President Jimmy Carter, and Iranian human rights activist Shirin Ebadi.