Don't Be a Sucker is an anti-fascist propaganda film produced by the United States Army Signal Corps. It follows a Freemason, Mike, who buys into the prejudiced beliefs of a demagogic street speaker until the speaker denounces Masons. A European refugee then speaks to Mike about how the same prejudiced beliefs led to the rise of fascism in Germany. The film argues that both majority and minority groups are harmed by fascism, and that Americans must unify against fascism regardless of race, religion, or national origin. Don't Be a Sucker saw a resurgence in popularity after the Unite the Right rally in 2017.

The film opens with descriptions of different types of suckers, describing a man who is robbed after falling for honey trapping and a man duped into losing money in a poker game. It then cuts to Mike, a proud American. It shows all the different demographic groups that make up the U.S., and the narrator warns that Mike is a potential victim of those who wish to rob him of his birthright to live in a multicultural U.S. community. Mike listens to a street speaker ranting about minority groups and agrees until the man disparages Freemasons, as Mike himself is a Mason. A professor introduces himself as a European refugee and asks Mike about his reaction. He tells Mike that the man is trying to manipulate the audience and that the same thing happened in Berlin.

The professor tells Mike about a Nazi street speaker who made similar arguments to the American street speaker. He describes how the Nazi speaker divided the minority groups in Berlin. He describes Hans—a model German according to Nazi ideals—as the listener who was deceived the most. Hans believed that he would benefit from the Nazis by sacrificing the rights of minorities, but he instead lost his own freedom, dying far from home for a fascist regime. The professor describes how everyone suffered as the Nazis took power, telling of a German educator who challenged the idea of a master race only to be assaulted by Nazis. The professor concludes that everyone is a minority in some way and that Americans should see themselves as a united group instead of individual demographics. Mike is convinced, and he rips up the pamphlet given to him by the prejudiced American speaker.

Don't Be a Sucker is an anti-fascist propaganda film created by Richard Collins. It was produced by the United States Army Signal Corps, and distributed by Paramount Pictures. The film stars Paul Lukas, Felix Bressart, and Kurt Kreuger, and it is narrated by Lloyd Nolan. It was produced in 1945, and Paramount Pictures allowed showings for the public "without profit" in 1946. 21st century sources describe a 1943 production and 1947 release instead of 1945 and 1946. The film was later withdrawn from public viewing.

Don't Be a Sucker was created under the initiative of the National Conference of Christians and Jews, and it was the final short film produced by the Army Signal Corps in World War II. It was one of many propaganda films at the time to use the rise of fascism in Germany as a cautionary tale. The film was produced during a time of racial segregation in the United States and the internment of Japanese Americans, which directly conflicted with the film's message. It was originally produced for viewing by American soldiers in World War II, and it sought to challenge the ideas of segregation that were common at the time.

Don't Be a Sucker challenges prejudice against minorities and warns viewers against complacency in the face of discrimination. Through an appeal to self-interest, the film argues that prejudiced people are being manipulated and do not benefit from prejudiced behavior. It warns that democracy can be broken when the people are divided and that prejudice can cause this. The film provides an alternative to prejudice, arguing in favor of an American populace unified by the ideal of liberty and its protection. Don't Be a Sucker maintains that everyone suffers under fascism, including the groups that the fascist regime allegedly protects. In contrast to the film's anti-fascist position, its villain supports antidemocratic and demagogic ideals.

Don't Be a Sucker was intended to reach a variety of demographics, and appeals to specific minority groups were included throughout. Instead of addressing why fascist beliefs take hold in society, the film remains palatable to the audience by portraying Nazis as manipulators. Separate messages are delivered for viewers in majority or minority groups. Majority groups are told that giving in to prejudice will make the majority subject to fascism, and minority groups are told that they are stronger if they remain united against the threat of fascism. Among religious groups, Catholics, Protestants, and Jews were shown to suffer from prejudiced beliefs. The film creates a feeling of isolation during the street speaker sequence by having the other listeners step away from the Jewish and Catholic listeners as their specific groups are named by the street speaker. The film indirectly addresses the belief that immigrants and African Americans will take the jobs of White Americans. Though it does not directly decry employment discrimination, this is one of the issues on which the street speaker bases his prejudiced arguments.

A 1951 study conducted by Eunice Cooper and Helen Dinerman found that viewers of Don't Be a Sucker engaged in selective perception for arguments that conflicted with their preconceived beliefs. In some cases, this included viewers interpreting the film to support ideas that do not reflect the intended message or contradict it outright. They found that viewers of the film were more likely to say that fascism could never occur in the United States. The film's emphasis on minority groups instilled in participants the belief that these groups are too numerous for fascism to be a serious threat.

Participants in the study also struggled to take the characters seriously. They saw the American street speaker as harmless and laughable compared to the Nazi street speaker, deeming him ineffective in spreading fascist ideas. They saw Mike as unrelatable because he was "weak, gullible, and passive". The film was found to be successful in discouraging employment discrimination. One quarter of Protestants who viewed the film in this study believed that American-born citizens should be given preferential treatment in employment, compared to one half of Protestants who did not view the film.

Don't Be a Sucker saw increased popularity beginning in 2016. A two minute clip from the film was widely shared on the internet in August 2017 in response to the Unite the Right rally in Charlottesville, Virginia. Many celebrities and public figures shared the video, including Congressman Keith Ellison from Minnesota and Professor Michael Oman-Reagan of Memorial University of Newfoundland. Those sharing the video made comparisons between the plot of the film and more recent nativism in American politics, deeming it relevant to Trumpism and white nationalism. Various copies have been uploaded to video-sharing sites since then.

• First they came ... – Statement and poem attributed to pastor Martin Niemöller
• The House I Live In – 1945 film by Mervyn LeRoy

• Don't be a Sucker at IMDb
• Don't Be a Sucker download on the Internet Archive (17 minute version)
• Don't Be a Sucker download by Prelinger Archives on the Internet Archive (17 minute version)
• Don't Be A Sucker on YouTube (23 minute version)