Meghan L. O'Sullivan (born September 13, 1969), a former deputy national security adviser on Iraq and Afghanistan and now a lecturer and senior fellow at Harvard University's John F. Kennedy School of Government Belfer Center for Science and International Affairs.
She received her bachelor's degree from Georgetown University in 1991. O'Sullivan later received her master's degree in economics and her D.Phil. (Ph.D.) in politics from the University of Oxford. Her doctoral dissertation was about the Sri Lankan Civil War
O'Sullivan has also served in the Office of Policy Planning at the State Department, where she assisted Colin Powell in developing the smart sanctions policy proposal; as an assistant to Paul Bremer in the Coalition Provisional Authority subsequent to the 2003 invasion of Iraq; and as Senior Director for Iraq at the National Security Council. O'Sullivan last position at the White House was as the Special Assistant to the President and Deputy National Security Advisor for Iraq and Afghanistan.
During her time in Iraq, O'Sullivan was involved with many key decisions on the political front, including helping negotiate the early transfer of sovereignty to the Iraqis and assisting the Iraqis in writing their interim constitution. She is remembered for driving herself around Baghdad to meet with Iraqis, and endured some harrowing experiences while in Iraq, including escaping from a terrorist attack by scaling a building ledge ten stories up.
In Washington, several policy insiders have credited her with being one of the original architects of the "surge" strategy that led President Bush to send more troops to Iraq in 2007. 
In 2003 Defense Secretary Donald Rumsfeld told Jay Garner that he could not keep her on in Iraq, though Rumsfeld later relented.
Critics inside and outside the Bush administration also charged that O'Sullivan had little background in Iraq and Afghanistan, the areas on which she was advising the President. O'Sullivan "is not an expert in the field" wrote David Corn.
An Afghan expert meeting with O'Sullivan at the White House in 2006 reportedly discovered that she had never heard of the Durand Line, the disputed border between Afghanistan and Pakistan. 
Her resignation was announced April 2 2007. Professor Larry Diamond of Stanford University, formerly of the Coalition Provisional Authority, said of O'Sullivan's resignation, "The administration's policy has been a tragic failure, and she has been a central element of our policymaking" but "the majority of the blame needs to rest at the foot of the higher officials,".
Diamond had previously recommended her not to get involved with Iraq because he then saw the strategy as failing, and did not want her to be associated with a failing war.
On May 31, 2007, President Bush announced that Meghan was returning to Baghdad "to serve with Ambassador Crocker, to help the Iraqis -- and to help the Embassy help the Iraqis -- meet the benchmarks that the Congress and the President expect to get passed."
On September 15, Meghan left the White House and began teaching at Harvard three days later.