Bin Laden, who was top of the US "most wanted" list, was accused of being behind a number of atrocities, including the attacks on New York and Washington on 11 September, 2001.
The development comes just months before the 10th anniversary of the attacks, in which nearly 3,000 people died.
US President Barack Obama
Tonight, I can report to the American people and to the world that the United States has conducted an operation that killed Osama Bin Laden, the leader of Al-Qaeda, and a terrorist who's responsible for the murder of thousands of innocent men, women and children.
For over two decades, Bin Laden has been al-Qaeda's leader and symbol, and has continued to plot attacks against our country and our friends and allies. The death of Bin Laden marks the most significant achievement to date in our nation's effort to defeat al-Qaeda.
Yet his death does not mark the end of our effort. There's no doubt that al Qaeda will continue to pursue attacks against us. We must - and we will - remain vigilant at home and abroad.
As we do, we must also reaffirm that the United States is not - and never will be - at war with Islam.
Former US President George W Bush
This momentous achievement marks a victory for America, for people who seek peace around the world, and for all those who lost loved ones on September 11, 2001.
Former US President Bill Clinton
This is a profoundly important moment not just for the families of those who lost their lives on 9/11 and in al-Qaeda's other attacks but for people all over the world who want to build a common future of peace, freedom, and co-operation for our children.
I congratulate the president, the National Security team and the members of our armed forces on bringing Osama bin Laden to justice after more than a decade of murderous al-Qaeda attacks.
UK Prime Minister David Cameron
The news that Osama Bin Laden is dead will bring great relief to people across the world.
Osama Bin Laden was responsible for the worst terrorist atrocities the world has seen - for 9/11 and for so many attacks, which have cost thousands of lives, many of them British.
It is a great success that he has been found and will no longer be able to pursue his campaign of global terror.
Israeli Prime Minister Benjamin Netanyahu
This is a resounding triumph for justice, freedom and the values shared by all democratic nations fighting shoulder to shoulder in determination against terrorism.
New York Mayor Michael Bloomberg
After September 11, 2001, we gave our word as Americans that we would stop at nothing to capture or kill Osama bin Laden. After the contribution of millions, including so many who made the ultimate sacrifice for our nation, we have kept that word.
The killing of Osama Bin Laden does not lessen the suffering that New Yorkers and Americans experienced at his hands, but it is a critically important victory for our nation - and a tribute to the millions of men and women in our armed forces and elsewhere who have fought so hard for our nation.
New Yorkers have waited nearly 10 years for this news. It is my hope that it will bring some closure and comfort to all those who lost loved ones on September 11, 2001.
House Speaker John Boehner
This is great news for the security of the American people and a victory in our continued fight against al Qaeda and radical extremism around the world. We continue to face a complex and evolving terrorist threat, and it is important that we remain vigilant in our efforts to confront and defeat the terrorist enemy and protect the American people.
I want to congratulate - and thank - the hard-working men and women of our Armed Forces and intelligence community for their tireless efforts and perseverance that led to this success. I also want to commend President Obama and his team, as well as President Bush, for all of their efforts to bring Osama bin Laden to justice.
US Senator John McCain
I am overjoyed that we finally got the world's top terrorist. The world is a better and more just place now that Osama Bin Laden is no longer in it. I hope the families of the victims of the September 11 attacks will sleep easier tonight and every night hence knowing that justice has been done. I commend the president and his team, as well as our men and women in uniform and our intelligence professionals, for this superb achievement.
But while we take heart in the news that Osama Bin Laden is dead, we must be mindful that al-Qaeda and its terrorist allies are still lethal and determined enemies, and we must remain vigilant to defeat them.
House Majority Leader Eric Cantor
Tonight, we've learned that justice has been done. The man with the blood of more than 3,000 Americans on his hands, the man who forced us to begin to think the unthinkable - is now dead.
Families who lost loved ones at the hands of Bin Laden and his terrorist organization have grieved for far too long and this sends a signal that America will not tolerate terrorism in any form. The men and women of our armed forces and intelligence community have fought valiantly for the last decade and this is a major victory and testament to their dedication. I commend President Obama who has followed the vigilance of President Bush in bringing Bin Laden to justice.
US Senator Joe Lieberman
The death of Osama Bin Laden unfortunately does not mean the end of the al-Qaeda network he built, the hateful ideology he helped propagate, or the threat against our homeland. Terrorists will continue to seek to murder Americans at home and abroad, and so too must our ever more determined global efforts to thwart their plots, destroy their networks, and defeat their ideology.
But the end of Osama bin Laden - at American hands, and in partnership with a Muslim ally - marks a historic victory in this longer struggle. Bin Laden's death should bring a measure of justice and solace to al Qaeda's victims, and fear to its ranks, who now must know their hour of reckoning, too, shall come.
US Senator Richard Lugar
The reported death of Osama Bin Laden is welcome news, but it in no way eliminates the threat from the terrorism he espoused. This is another reminder that Americans cannot hide from global affairs.
Americans must continue to be vigilant to ensure that terrorist groups and rogue states do not obtain weapons of mass destruction, a goal that I and many other Americans have sought for 20 years.
US Senator Susan Collins
This welcome news is a credit to our intelligence efforts and brings to justice the architect of the attacks on our country that killed nearly 3,000 people on September 11, 2001.