The theories

“9/11 was an inside job”

The big theory, what it rests on, and how many people believe it

RECORD / AT A GLANCE

False

False as a claim that the U.S. government planned or carried out the attacks. Every core piece of the theory has a documented answer. What is true is serious enough on its own: the government had warnings it failed to act on, agencies misled investigators, and some evidence was withheld for years.

THE EVENTS / THE INVESTIGATION / THE STORY

The chronology.

READ THE FILE

Evidence & assessment.

Open an article for its evidence, labeled AI assessment and numbered sources. Read the complete static edition ↗

WHAT PEOPLE SAY ABOUT THIS FILE

The claims, rated.

2 claims people make about this file, each rated documented, partly true, disputed, unproven or false. Think a rating is wrong? Use Dispute or Support, or join the Discussion.

FALSE Inside job, money & viral theories

“9/11 was an inside job.”

Every core piece of the theory has a documented answer. The real failures, the misleading accounts and the withheld evidence do not show the government planned it.

Who says it: Truth movement; 20% of Americans in 2023.

The evidence in this file ↗ · On the full claims board ↗

All 162 rated claims ↗

OPEN THE RECORD

Sources & limits.

Numbered citations in each article identify the relevant sources. These records have different purposes and evidentiary weight.

  1. NIST NCSTAR 1: Final Report on the Collapse of the World Trade Center Towers (2005) ↗

    The federal investigation’s report on why the towers fell.

  2. NIST NCSTAR 1A: Final Report on the Collapse of World Trade Center Building 7 (2008) ↗

    Fire-induced thermal expansion, the Floor 13 girder and Column 79.

  3. ASCE (Mlakar et al.), January 2003: The Pentagon Building Performance Report (NIST copy) ↗

    Engineers’ study of the damage path from Flight 77 through the building.

  4. 9/11 Commission Report, chapter 1: “We Have Some Planes” ↗

    The minute-by-minute account of the four flights and of the FAA and NORAD response, including the 10:03:11 crash time of United 93 and when the shootdown order reached the pilots.

  5. 9/11 Commission Report, chapter 8: “The System Was Blinking Red” ↗

    The summer 2001 threat reporting, the 6 August PDB, the Phoenix memo, Moussaoui and the missed chances on Hazmi and Mihdhar.

  6. YouGov, 2023: Which conspiracy theories do Americans believe? ↗

    20% said the government was behind the attacks was definitely or probably true.

  7. Democracy Now!, 11 September 2006: Loose Change filmmakers debate Popular Mechanics ↗

    A long, even-handed debate between the two sides.

  8. New York Times, 2 January 2008: “Stonewalled by the C.I.A.,” by Thomas H. Kean and Lee H. Hamilton ↗

    The Commission’s chairman and vice chairman say the CIA never told them about interrogation videotapes it later destroyed. Blocks scripted fetches; confirmed by search.

  9. DW, September 2026: 9/11 conspiracy theories that continue to circulate ↗

    Which theories still spread 25 years on. Confirmed by search.

← The 9/11 hub: the story, the full timeline and every file

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