"Your brilliant victory rewards a tireless commitment to serve the American people," The Daily Telegraph quoted French President Nicolas Sarkozy as saying.
Kenyan President Mwai Kibaki called it a "momentous day" for the United States and Kenya, as well.
"The victory of Senator Obama is our own victory because of his roots here in Kenya. As a country, we are full of pride for his success," Kibaki said.
British Conservative Party Leader David Cameron said Obama had "made history and proved to the world that it is a nation eager for change."
Another African leader, Somali President Abdullahi Yusuf Ahmed, expressed hope Obama would "help end major crises in the world, particularythe endless conflict in my country Somalia."
The BBC reported European Commission leader Jose Manuel Barroso said he hoped Obama's election signaled that the United States will "join forces with Europe" to force "a new deal for a new world."
"France, Europe and the international community need his energy, his rejection of injustice and his determination to go forward to build a safer, fairer and more stable world," Barroso said.
Iraqi Foreign Minister Hoshyar Zebari said Obama will face many challenges.
"We don't think there will be change in policy overnight. There won't be quick disengagement here," Zebari said. "A great deal is at stake here."