9 Most Believable Conspiracy Theories (Ranked by the Evidence)
9 Most Believable Conspiracy Theories (Ranked by the Evidence)
Most lists of the most believable conspiracy theories are really lists of the most popular ones. Lizard people are popular. What we wanted to know is different: which unproven theories actually hold up when you put the official record on the table next to them?
So here is how we ranked these. For every theory we start with what the official investigation concluded, by name. Then we list the documented facts that make the theory reasonable to entertain, from government reports and court records, not YouTube comments. Then we name the leap: the part nobody has proven yet. The smaller the leap and the stronger the documented facts, the higher the theory sits on the list.
One rule: this page is about theories that are still unproven. Confirmed cases like MK Ultra and the Tuskegee study live on a different page. The believability scores are our opinion, made by three guys with a podcast, not a verdict.
1. JFK: Oswald did not act alone
The granddaddy of them all, and still the one with the most official ammunition behind it.
The official story: The Warren Commission concluded in 1964 that Lee Harvey Oswald, the accused assassin, fired the shots and acted alone. Oswald was killed two days later and never stood trial.
Why it is believable: A second official investigation disagreed. In 1979 the House Select Committee on Assassinations agreed that Oswald fired the shots that killed Kennedy, but its published findings say Kennedy “was probably assassinated as a result of a conspiracy” and that acoustic evidence pointed to a second gunman. The public never let go either: in Gallup’s 2023 poll for the 60th anniversary, 65% of Americans said others were involved.
What is still missing: The committee itself said it could not identify the other gunman, and its acoustic evidence was later challenged by other scientists.
Believability: 8 out of 10. An official body already said “probably,” which is more than any other theory here can claim.
Our episode: Who Killed JFK?
2. MLK: James Earl Ray had help
The only theory on our list that a jury has actually agreed with.
The official story: James Earl Ray pleaded guilty in 1969 to killing Dr. Martin Luther King Jr. in Memphis. He tried to take the plea back within days and claimed until his death in 1998 that he was framed by a man he called Raoul.
Why it is believable: The same 1979 House committee found that Ray fired the shot, but also that there was “a likelihood” he did it “as a result of a conspiracy.” Then in 1999 a civil jury in Memphis, in a lawsuit the King family brought against a local tavern owner, found that he and unnamed others, including government agencies, took part in a conspiracy. Add the FBI’s well documented COINTELPRO campaign against King, and you can see why his own family stopped trusting the official version.
What is still missing: In 2000 the Justice Department investigated the claims and found them not credible, calling the trial’s allegations of a government plot conflicting hearsay. No government agency was a defendant in that lawsuit, so nobody presented the other side. The 1979 committee also said no government agency was involved. Nobody has proven who the co-conspirators were.
Believability: 7 out of 10. Two official findings point to “more than Ray,” even if they disagree on who.
Our episode: The MLK Assassination Revisited Part Three: The Conspiracies
3. RFK: There was a second gunman
Less than five years after Dallas, another Kennedy, another crowd of witnesses, and another set of numbers that do not quite line up.
The official story: Sirhan Sirhan was convicted of murdering Senator Robert F. Kennedy, who was shot at the Ambassador Hotel in Los Angeles in June 1968.
Why it is believable: According to the coroner, the fatal bullet entered behind Kennedy’s right ear, and powder burns showed the gun was only 1 to 1.5 inches away, a detail recorded in the FBI’s own case summary. Sirhan was in front of Kennedy when he fired. His revolver held eight rounds, yet a 2008 analysis of a surviving audio recording, reported by The Guardian, counted 13 shots.
What is still missing: The 13 shot count comes from one analysis of a poor quality recording, and no second shooter has ever been identified.
Believability: 6 out of 10. The autopsy problem is real, the second gunman is still a ghost.
Our episode: The Assassination of RFK Part Three: Patsy or Lone Gunman
4. Lincoln: The Confederate government was behind Booth
Fun fact: the Lincoln assassination was a conspiracy. That part is not a theory. The question is how far up it went.
The official story: In 1865 a military commission convicted eight people of conspiring with John Wilkes Booth, and four of them were hanged. Booth himself was killed before he could be tried.
Why it is believable: In May 1865 President Andrew Johnson issued a proclamation saying the assassination was “incited, concerted, and procured” by Jefferson Davis and Confederate agents in Canada, with rewards for their arrest. According to the National Park Service, Booth traveled to Montreal while planning to kidnap Lincoln and likely met members of the loose “Confederate Secret Service” there. The Park Service also says other Confederate agents may have been plotting to take Lincoln hostage too.
What is still missing: The government planned to try Davis before a military commission for the assassination, then switched to a treason case, and that case was eventually dropped. He was never tried for Lincoln’s murder, and no document has surfaced showing Confederate leaders ordered a killing rather than, at most, a kidnapping.
Believability: 6 out of 10. A proven conspiracy with a very believable, still unproven top floor.
Our episode: Lincoln: Conspiracy! Part One
5. The government knows more about UFOs than it says
Not “aliens are real.” The more modest, more believable version: officials have kept more UFO information quiet than they admit.
The official story: The Pentagon’s All domain Anomaly Resolution Office said in its 2024 historical report that it found no empirical evidence the government or private companies ever had extraterrestrial technology.
Why it is believable: The government has a track record here. In December 2017 The New York Times revealed that the government had run a program investigating UFO reports until 2012. In April 2020 the Pentagon officially released three Navy videos that fighter pilots recorded in 2004 and 2015. In July 2023 a former intelligence official testified under oath to a House committee that he “was informed” of a multi decade crash retrieval program. Congress cared enough to create a dedicated UAP records collection at the National Archives in its 2024 defense bill.
What is still missing: Testimony is not evidence you can hold. Nobody has produced a craft, a body, or a document proving a retrieval program.
Believability: 6 out of 10. “They are hiding files” is very believable. “They are hiding a spaceship” is a much bigger leap.
Our episode: What Is Really Inside Area 51?
6. Pearl Harbor: Roosevelt knew it was coming
The original “they let it happen” theory, and the template for a lot of what came after.
The official story: Congress’s joint investigating committee released its report in 1946 with 22 conclusions and recommendations, focused on fixing how intelligence was coordinated and shared, not on any plan to let the attack succeed.
Why it is believable: American codebreakers had been reading Japan’s diplomatic messages for years through a program called MAGIC. A Navy intelligence memo from October 1940 listed eight actions against Japan and added that if Japan could be led to commit “an overt act of war, so much the better.” Early in 1941 the U.S. ambassador in Tokyo even reported that Peru’s minister had told American diplomats Japan planned a surprise attack on Pearl Harbor if trouble came.
What is still missing: Japan’s navy used different codes that Americans had not fully broken, and the strike force sailed under radio silence. No document shows Roosevelt choosing to let the fleet get hit.
Believability: 4 out of 10. The codebreaking was real, the smoking gun is not.
Our episode: Pearl Harbor: Part One
7. 9/11: They knew and let it happen
The facts about missed warnings are official. The leap from “missed” to “allowed” is where it gets shaky.
The official story: The 9/11 Commission Report found four kinds of failure across government, in imagination, policy, capabilities and management, not a decision to allow the attacks.
Why it is believable: The Commission itself documented how much was known. A President’s Daily Brief on August 6, 2001 was titled “Bin Ladin Determined to Strike in US.” The CIA learned in March 2000 that one future hijacker had flown to Los Angeles, yet he and a fellow hijacker were not added to a watchlist until August 24, 2001. The Commission titled a whole chapter “The System Was Blinking Red.”
What is still missing: Everything that would turn negligence into intent. No document, witness or investigation has shown anyone deciding to let the attacks happen.
Believability: 3 out of 10. The warnings are a matter of record, the “let it happen” part is not.
Our episode: 9/11: Unanswered, our full series
8. Roswell: It was not a balloon, it was a spacecraft
The rare case where the government admits it told a cover story, and the theory still does not win.
The official story: In 1994 the Air Force said the 1947 debris came from Project Mogul, a classified balloon project. A 1997 follow up, “The Roswell Report: Case Closed,” said the alien bodies people described were probably test dummies carried aloft by Air Force balloons.
Why it is believable: On July 8, 1947, Roswell Army Air Field put out a press release saying it had recovered a “flying disc.” The next day the story became a weather balloon. Decades later the Air Force said it was not an ordinary weather balloon either. Change your story twice and people stop trusting the third version.
What is still missing: Any physical evidence of something not made on Earth. The proven cover-up was about a spy program, which fits every documented fact without aliens.
Believability: 3 out of 10. The cover story was real, the spaceship is not supported.
Our episode: What Really Happened at Roswell?
9. Marilyn Monroe was murdered
A Hollywood death with a Kennedy shaped shadow, which is all it takes to start sixty years of theories.
The official story: Marilyn Monroe died in August 1962 of acute barbiturate poisoning, and her death was ruled a probable suicide. A 1982 Los Angeles district attorney review found “no credible evidence supporting a murder theory.”
Why it is believable: The FBI kept a file on her, and the murder theories that pushed for the 1982 review claimed she died soon after a romance with Robert F. Kennedy ended. That same review admitted “factual discrepancies” and “unanswered questions” remained. Even a lawyer from the DA’s office who attended her autopsy later doubted the suicide ruling, according to his 2011 obituary in the Sydney Morning Herald.
What is still missing: A suspect, a motive anyone can prove, and any physical evidence of foul play.
Believability: 3 out of 10. Loose ends, yes. Evidence of murder, no.
Our episode: How Did Marilyn Monroe Die?
How we ranked these
We scored every theory on two things. First, how strong is the documented record that makes it reasonable? An official body saying “probably a conspiracy” counts for a lot. A rumor in a tabloid counts for nothing. Second, how big is the leap the theory needs to make beyond that record? A second gunman nobody can name is a smaller leap than a spaceship nobody can find.
We left out theories that are already proven, theories that only work by accusing a living person, and theories that are mostly vibes, which is why the Bermuda Triangle and the moon landing hoax are not here.
Believable is not the same as true
A theory can be reasonable to wonder about and still be wrong. The reason so many people entertain the ones above is that governments really have lied before, and some conspiracies did turn out to be real. If you want the ones that were proven, read our list of true conspiracy theories. If you want to check the documents yourself, start with our guide to the best conspiracy websites for research.
