Top 20 Conspiracy Theories That Became Shockingly Influential

#20: The 2020 Election Was Stolen

Although the effects came to a head following Joe Biden’s win, it goes back much further than that. Republicans’ history of election denialism spans decades. With the seeds of distrust having been sewn, Trump was easily able to convince his base that his 2020 loss was fraudulent. Some outlets in mainstream media upheld the theory, and alleged that rigged machines and illegal immigrants voting were to blame. It became a common belief amongst the right, with politicians and voters alike bolstering it. When Trump reclaimed the White House in 2024, his administration used the mass doubt to alter future elections. Between the recent restrictions on mail-in ballots and the House-approved SAVE Act requiring proof of citizenship, it seems the conspiracy may impact the nation for years to come.

#19: COVID-19’s Origin & Vaccination Misinformation

In 2020, the world at large was sent into a tailspin with the onset of the coronavirus pandemic. It didn’t take long for conspiracies to form, particularly around its origin and the vaccines preventing it. Social media and right-wing propaganda fanned the flames, and before long a significant portion of the United States population believed that it had been created and inflicted upon the world by the Chinese government. This led to the virus spreading, with dissenters decrying masks and social distancing. The vaccine rollout in 2021 bolstered that suspicion further, with claims ranging from them altering DNA to tracking citizens. Both theories combined eroded the public’s trust in the scientific community, and in many places around the world, it has yet to be regained.

#18: The Great Reset

COVID-19 didn’t just have an impact on science. In response to the pandemic, the World Economic Forum released a statement on how they would mitigate financial harm in its wake. It was dubbed The Great Reset, and thus a new conspiracy was born. Social media quickly spread the idea that the global elite planned to control the economy, and that the pandemic had been created in order to do so. Others purported that capitalism would be forcibly overturned in favor of widespread communism. The theory quickly gained prominence internationally, with several important leaders being decried for supporting it. It’s resulted in a mass nationalism movement and an increase in skepticism towards the government in several countries around the world.

#17: Vaccines Causing Autism

Despite all the help they’ve brought in limiting disease worldwide, that hasn’t stopped conspiracies from denigrating some peoples’ trust in them. Since the 1990s, theories that the Measles, Mumps, & Rubell vaccines cause autism have thrived amongst some communities. Andrew Wakefield’s research and the subsequent media attention it received led to a global scare and vaccination rates dropping in multiple countries. Although he was eventually proven fraudulent, the damage was done. Misinformation surrounding shots of all kinds has flourished online, leading to even lower rates and the return of once-eradicated diseases in the United States. In 2025, Wakefield’s original scheme made an alarming comeback thanks to the Centers for Disease Control and Prevention claiming legitimizing it, ensuring that the misinformation wouldn’t die anytime soon.

#16: The Reptilian Elite

It may have been largely formed in myth, but its impact on society has been all-too-real. The idea that shapeshifting humanoid reptilians control the government has persisted, with theorists like David Icke making it mainstream. The prominence of the symbolism in religion and in fiction have caused it to become a far-reaching belief around the world. Various international leaders and nominees have used the conspiracy against their opponents in elections or have claimed it as fact, which has led to its continued popularity amongst millions of people in the United States alone. Increased confidence in the theory has led to an uptick in violence as well, with some believers using it as justification for slaying their loved ones or carrying out acts of domestic terrorism.

#15: Project MKUltra

Sometimes, the scariest conspiracies are those rooted in truth. In 1975, an investigation uncovered a twenty-year long program held by the CIA. Known as MKUltra, the revelation showed that the government agency had used a litany of methods to try and take control of people’s minds. Several of the documents were destroyed prior to it being uncovered, leading the public to fill in the details for themselves. Several theories were speculated, including that certain criminals had been tested on and that the agency is still conducting these experiments. Although there was a degree of transparency from the United States government following the investigation and records being released, it caused a mass wave of distrust against them that has yet to be regained.

#14: Satanic Panic

With social change came extreme pushback.Throughout the 1980s, the rise of cultural phenomena like metal music and expanding day care use contributed to increased fears about Satanism. It began in the 1980s, and soon made its way across the globe. It was bolstered by the news, and soon countless accusations of abuse in the name of Satan were made. Innocent people around the world were wrongfully accused and even imprisoned as a result of the mass conspiracy. Even after the initial craze died down, it still had a considerable impact on politics. Modern-day candidates have attempted to drum up fear against their opponents by associating them with Satanism, ensuring that it won’t leave the public mind any time soon.

#13: Flat Earth Theory

It may seem easily debunkable, but that hasn’t lessened its impact one bit. The theory that the Earth is flat rather than spherical dates back to ancient times, and has persisted well into the modern era thanks to celebrity endorsements and the rise of social media. By the end of the 2010s, conferences in support of the misinformation had been held in several countries. It has persisted despite the ample evidence proving otherwise. This has revealed both an increased distrust in science itself and in agencies that have run tests to disprove it. Believers have questioned everything from astronaut’s experiences to photos of the planet, which has helped it remain one of the most widespread conspiracies around the world.

#12: QAnon

Conspiracies born from the Internet have been just as harmful as those that came before it. QAnon first rose to prominence in the 2010s on 4chan, and claimed to be an insider within the Trump administration. It quickly circulated online and soon breached into the mainstream, where it became a widely followed movement. Multiple conservative politicians have pushed the theory, which only legitimized it in the eyes of believers. Its popularity has had disastrous consequences. Several of its followers have committed crimes to spread it, from kidnapping to attempted domestic terrorism. It came to a head in early 2021, when individuals linked to QAnon participated in the storming of the U.S. Capitol. Though it’s a newer ploy, its impact has already proven to be astronomical.

#11: 9/11 Was an Inside Job

Would a country really attack its own citizens? For many that believe the United States government had a hand in the attacks on September 11th, 2001, that answer is a resounding yes. Theories circulated online hours afterwards, they went global, with various claims popping up in Europe. Since then, it’s become one of the most pervasive conspiracies in modern history. Trutherism quickly rose to prominence, and led to alt-right figures like Alex Jones being platformed. It’s been pushed by politicians, with elected officials promoting it and conspiratorial thinking alike. The tragedy's legitimacy has been questioned by various world leaders and citizens, which has all but ensured that people at large will continue to question it for years to come.

#10: President John F. Kennedy’s Assassination

He may not have been the first politician to have been slain in office, but his death has remained on the forefront of conspiratorial thinking for decades. Theories about the supposed truth behind President John F. Kennedy’s assassination circulated almost immediately after the tragedy occurred. The first book of thousands on the subject was published in 1964, which cemented its prominence. Even after it was declared that Lee Harvey Oswald acted alone, the public’s opinion remained unchanged. This marked a permanent shift in American culture, where citizens no longer placed blind faith in their government. One poll in 2023 found that 65% of adults believed others were involved in Kennedy’s passing– and it doesn’t seem those numbers will see a significant drop any time soon.

#9: Chemtrails

Since 1996, some haven’t looked at the sky the same way. That year, the United States Air Force released a report where they discussed the concept of modifying weather events. This quickly spiraled into a full on conspiracy that the government was spraying the population with chemicals. The proof? Thin condensation lines left behind from aircraft. It didn’t take long for the theory to spread in forums online, and by the end of the century it was being pushed on radio shows as well. It has since become so rampant that multiple government officials from various countries have decried them. They have also impacted some people’s views on horrific weather events, with some even claiming they were the cause of a five-year drought in California.

#8: HAARP Weather Control

When it comes to conspiracies centered around the elements, chemtrails are just the tip of the iceberg. Around the same time they entered the public eye, authors began speculating that the United States government could use HAARP – otherwise known as the High-frequency Active Auroral Research Program – to create extreme weather events. Since then, natural catastrophes have been blamed on the program. They’ve been accused of manipulating both national and international catastrophes, with every storm appearing to bolster the support for it. The continued faith in the thesis has increased the anti-government mindset amongst many theorists. Not only has it all but overshadowed any positive work done by the program, it has also inspired some to plan domestic terrorist attacks against the facility.

#7: The Great Replacement

The conspiracies created to fan the flames of racism have proven to be some of the most dangerous. One of the most impactful has been the Great Replacement theory, which asserts that there is a plot to replace the white populace with people of color. This came about in the beginning of the 21st century amongst a growing dissent towards immigration. It has since seen immense global support, with countries across five continents claiming it to be real. Since becoming mainstream, it's proven to be extremely harmful. It’s led to an increase in racist and xenophobic attitudes. It has also inspired several horrific massacres carried out in the name of white supremacy, with many perpetrators citing or alluding to it in their manifestos.

#6: The Deep State

Although it’s been spoken about in a global context since the 1990s, it would take another twenty years before it reached the mainstream. The deep state theory, which posits that the government is being internally controlled by those within the private sector, first came to major prominence during Donald Trump’s initial presidency. With his influence, he was able to convince his base of millions that he was up against shadowy executive officials. This caused it to become a far-reaching belief amongst the conservative base. It’s resulted in an extreme level of wariness towards his enemies, with many calling for their arrest. It has also resulted in any pushback against him being disregarded as fake news from his dissenters, further muddying the waters of political discourse.

#5: The Moon Landing Was a Hoax

Although it was initially seen as one of the nation’s greatest accomplishments of the 20th century, it didn’t take long before it was twisted into a conspiracy. It all began in 1976, when a self-published novel claiming the moon landing had been faked hit the market. Skepticism continued to grow, and by the 21st century it had become a more widespread international sentiment. While it may not hold the same dangerous sentiment as other more volatile schemes, it has still had a considerable impact on society. It serves as an early example of trust in modern science and technology faltering. Beyond that, it also set the stage for other large events to be written off as fake, which allowed other conspiracies to form.

#4: Area 51 & Aliens

Given how confidential it is, it comes at no surprise that it’s been the source of several modern conspiracies. Whether its theories about the weapons potentially being developed or rumors of contact with aliens, the mystery surrounding Area 51 has made it the subject of worldwide interest. The latter had been a source of public intrigue since the late 1980s, and that only increased once the base was declassified in 2013. It had a palpable effect on pop culture, with it being referenced in various science-fiction works and becoming the subject of a viral meme-turned-raid. The predominant reliance on the hypothesis has also started to impact politics as well, with some candidates using the promise of declassifying documents as a way to garner support.

#3: Holocaust Denial

One might think that an event as horrific and tragic as the Holocaust would be universally acknowledged. Unfortunately, that isn’t the case. Conspiracies white-washing or outright denying the Holocaust began to spread throughout Europe shortly after World War II ended. It expanded into a global phenomena thanks to the United States’ Institute for Historical Review, which amplified the Antisemitic theory to a wider audience. The Internet broadcasted them even more, allowing them to become more accessible to people of all ages. The widespread misinformation has had plenty of consequences, such as other genocidal movements from around the world being denied. Holocaust denial has also contributed to modern acts of violence against Jewish communities, such as the 2018 Tree of Life synagogue massacre.

#2: “The Protocols of the Elders of Zion”

Misinformation has resulted in dangerous consequences. In the early 20th century, a fake manuscript detailing a supposed plot for Jewish citizens to take over was passed off as real. “The Protocols of the Elders of Zion” was then translated into different languages and sold all over the world, where it was taken as fact and amplified by influential figures, such as Henry Ford. It increased negative feelings and violence towards the Jewish community, and was even used by Nazi Germany to excuse their persecution of the population. It has remained impactful well into the 21st century, with some of its themes being used to create new conspiracies. The book has done untold damage so far– and there’s no telling how much more it will cause.

#1: The New World Order

While the belief that secret societies like the Illuminati rule the world has been part of fringe subcultures for decades, it rose to new prominence following the publication of “The New World Order” by Pat Robertson in 1991. The media did the rest of the work, with radio shows and the Internet alike spreading it far and wide. It has created extreme paranoia, with some believers scrutinizing every public event and figure in order to find proof of association. This has led to several celebrities being accused of being members. It doesn’t end there. Fear over the New World Order has also led to individuals committing acts of violence, which some experts fear will escalate even more should the panic around it become more prevalent.

Which of these conspiracies do you think has had the largest impact on society? Let us know in the comments below!