The CIA and September 11 is a controversial 2003 non-fiction book by Andreas von Bülow, a former state-secretary in the German Federal Ministry of Defence and a Social Democratic member of the Bundestag from 1969 to 1994. The book disputes al-Qaeda's responsibility for the September 11 attacks and suggests that it may have instead been a false flag operation arranged by the U.S. federal government and Israel. The book has enjoyed considerable commercial success in Germany, where it is published by Piper Verlag, and has sold over 100,000 copies. However, it has faced allegations ranging from absurdity and fostering anti-Americanism, to anti-Semitism, while the quality of its sourcing and the timing of its publication have given rise to debate within the German publishing industry. In subsequent media appearances, Bülow has defended his work, and strongly denied that its content is anti-Semitic.

Andreas von Bülow is a German politician of the Social Democratic Party (SPD) and writer. He was Minister for Research and Technology from 1980 to 1982. Von Bülow has authored books about intelligence agencies, including In the Name of the State. CIA, BND and the criminal machinations of secret services. and The CIA and 11 September. He holds a doctorate degree in Jurisprudence.