Oplan Bojinka (also known as Operation Bojinka, Project Bojinka, Bojinka Plot, Bojinga, possibly from Arabic: بجنكة – slang in many dialects for explosion and pronounced Bo-JIN-ka, except in Egyptian where it is Bo-GIN-ka) was a planned large-scale attack on airliners in 1995, and was a precursor to the September 11, 2001 attacks.

Several media outlets, including TIME Asia [1], claim that the word Bojinka means "loud bang" or "explosion" in Serbo-Croatian. In Croatian, "bočnica"[2] translates into English as "boom". Khalid Shaikh Mohammed fought with Muslim fighters in Bosnia and supported this effort financially [3]. Endnote 7 of Chapter 5 of the 9/11 Commission Report states that Khalid Shaikh Mohammed claims that "bojinka" is "a nonsense word he adopted after hearing it on the front lines in Afghanistan." In English, the acronym "BOHICA" for 'Bend Over Here It Comes Again' is common military slang which refers to an incoming enemy attack, often bombs and is also used in online chat, e-mail, or newsgroup postings.

Not all media or text that refer to Oplan Bojinka will call it by that name.

The term can refer to the "airline bombing plot" alone, or that combined with the "Pope assassination plot" and the "CIA plane crash plot". The first refers to a plot to destroy 11 airliners on January 21 and 22, 1995, the second refers to a plan to kill Pope John Paul II on January 15, 1995, and the third refers a plan to crash a plane into the CIA headquarters in Fairfax County, Virginia and other buildings. Oplan Bojinka was prevented on January 6 and 7, 1995, but some lessons learned were apparently used by the planners of the September 11 attacks. This article will cover all three plans.

The money handed down to the plotters originated from Al-Qaida, an international Islamic militant organization which was then based in Sudan. Philippine authorities say that Operation Bojinka was developed by Ramzi Yousef and Khalid Shaikh Mohammed while they were in Manila, Philippines in 1994 and early 1995.

Much of the media commentary on the busted plot in the UK has been referencing Operation Bojinka.